Unused Puzzle Types

While gathering puzzle types and their synonyms to add to indexed puzzles, I also encountered a number of puzzle types which are not represented in the index:

Crossword-type puzzles:

Boomerangs: 6-letter words are entered on curved paths bowing to the left and the right. Except for the words at the ends, each word shares two letters with each of three words entered the other direction.
Brick by Brick: A diagramless 15x15 crossword with an entry reading all the way across the middle row, with normal cluing. Additionally, the solution (excluding the middle entry, but including black squares) is broken up into 3x2 blocks which are provided in scrambled order.
Bricks and Mortar, Brick by Brick (again), or Super Sixes: A grid is given, divided by heavy bars into 2x4 sections. Numbered clues provide 8-letter answers to be entered starting at correspondingly numbered cells and proceeding in a direction for you to figure out around the brick. Adjacent letters across a heavy bar are identical. The Super Sixes version uses 6-letter answers and 2x3 bricks.
Color Wheels: A grid of triangles is given, with hexagonal holes between lines where you enter words. Three different colors of arrows mark where to enter words, one for words reading across, one for words reading diagonally upward, and one for words reading diagonally downward.
Diamond Rings: This puzzle features diamond-shaped spaces with a lattice of circles placed so as to occupy one or two opposite vertices of each diamond. The circles are numbered, and the answers to corresponding 5-letter clues are entered in a circle and its 4 adjoining diagrams, with the letters in no particular order.
5-Star Stumper: There are five pentagrams. Each is surrounded by 10 pentagonal spaces for letters, five between the arms of the star and 5 at the vertices. These are arranged in a loop so that one pentagon is shared by each pair of nearest stars. Two clues are give for words to enter around each star, with the starting cell and direction for each pair of words indicated by a number and arrow. In addition, the pentagons along the outer edge of the figure are shaded. A second set of clues is given for a sequence of words to be entered in this shaded path, clockwise, but starting at a point for you to determine. The unshaded cells in the interior spell a final message, row by row.
Hedgehogs and Worms: A grid is divided into 3x3 sections. The center square of each section is numbered, and an arrow points out of it into one of the 8 surrounding squares. Clues are given for the 9-letter hedgehog words which start in their correspondingly numbered squares, follow the arrow, and then continue clockwise or counterclockwise as indicated by a + or - after the clue. The sequence of worm words is clued in order, and are entered all the way across the rows of the grid which do not have the numbered squares, sometimes wrapping around from the end of one row to the start of the next. Letters in numbered squares provide a final answer.
Helter Skelter: Words read in 8 directions which are given implicitly in the grid, because each word starts at its number and passes through the next number sequentially. The last word's direction is not given.
Lucky Sevens: A grid is given made of seven heavily outlined 7-shapes (three squares across and five down) nested under one another. Labeled clues are given for the seven-letter words to be entered in each seven-shape and for each row of varying length, including the single letter at the bottom.
Moving Staircases: A square grid (typically 7x7) has the main top-left-to-bottom-right diagonal as black squares. Two sets of clues are given, not in grid order: "Short" answers go straigfht across a row, skipping the black square. "Long" answers climb up when they get to the black square, using the start of one short answer and the end of another.
Pencil Pointers, also called Arrow Routes: This is a standard crossword format in Scandinavian countries, imported for use in English. The grid cells are oversized, and terse clues are written into the gray (what would usually be black) cells. In some cases a gray cell is divided to hold two very short clues. Arrows next to the clues indicate where to enter the words. There is no symmetry and there may be a few isolated unchecked letters (including in the first row and column, with arrows stretching from adjacent gray cells providing the clues for the words starting there).
Pent Words: Clues are given for (usually two) words to be entered consecutively in each row. Clues are also given for 5-letter pentomino words, which are entered into nonoverlapping pentominoes you have to determine in the grid. The pentomino words are entered row by row in their pentominoes, even if this means a word skips over a gap in a U-shaped pentomino.
Quadruple Cross: The grid consists of some rows and columns of squares, two rows/columns apart so that there are 2x2 holes in the interior. The intersections are numbered, and clues for two 5-letter words are provided at each number, but you have to figure out which one goes across and which goes down by matching with answers at other intersections.
Retrograde Battleships: Shade in the fleet in the grid, so that no two ships touch, even diagonally, but instead of the normal numeric Battleships clues, the grid is filled with possible ship placements and you can only shade whole ships among them.
Section Eight: A round grid with 8 rings is divided into 8 sectors. The innermost ring has one letter in each sector, the next ring out two, and so on to eight letters per sector in the outermost ring. Clues are provided for one word per every eight letters in each of the rings, though the answers may vary in length. In the outermost ring you are given the starting spaces for all the words and hence their lengths. Elsewhere you have to determine the starting spaces and the direction the words go, which can be different for each ring. In each sector, the letters in each ring are a transdeletion of the letters in the next outer ring in the same sector, though these letters are usually parts of one to three words and not a whole clued word. There is also a Section Six version of this puzzle which uses 6 of everything the Section Eight version has 8 of.
Slot Machine: Clues are given for words entered across each row. Clues are also given for words reading down each column, but the column words may start anywhere in the column and wrap around.
Snake Charmer: Words are entered consecutively along a long loop (which is presented in an S shape to resemble a snake). The words go twice around the loop, entered consecutively but overlapping words from the other pass. Answer locations are numbered in order (so there are two interleaved sequences of increasing numbers around the loop).
Snake Crisscross: A criss-cross-style grid is given, and clues are given for the words to be entered, sorted alphabetically by answer within each length. Additionally, snake words are clued with the same sorting; the grid can be divided into nonoverlapping winding paths to reuse the same letters to spell the snake answers. The snake paths may or may not be given using heavy outlines.
Sunburst: A round grid has a single circle at the center and 4 rings around it with the same number of cells in each ring. Two sets of clues are given, short words and long words. The long words are entered in the grid and all end with the same single letter at the center. The short words are transdeletions of the long word. The outermost ring is numbered and the short words are numbered to match; the long clues are not numbered.
Touchword: Clues are given for answers to be entered consecutively in each row. There are no actual crossings, but each letter must match either the one above it or the one below it or both, wrapping around from the bottom to the top of the grid.
Triangle Tangle: A zigzagging grid of right triangles is given. The 4 letter answers alternately read straight down and diagonally up and right, so that each "up" word is a reversal of the last two letters of one down answer plus a reversal of the first two letters of another. The puzzle type Back and Forth (which is in the index) is similar but with three-letter halves instead of 2.
Zigzagnut: A grid of squares is given, divided by heavy borders into paths which alternate steps across and down. These regions are numbered and provided with a clue for each. There are also clues for two words reading across each row which are given in order but you are not told which row each pair of clues goes with.

Other word puzzles:

Alphablocks: The alphabet is printed in a column with spaces on both sides. 52 trigrams are given in alphabetical order. Add one trigram on each side of each letter to form 26 7-letter words.
Anagram Magic Square: 25 numbered clues are given. An oversized 5x5 grid contains a word in each cell, but the clue answers are transadditions of each given word. The cells are not numbered; instead, you add the numbers to the cells as you solve; these numbers will form a magic square when the puzzle is complete, and the extra letters spell a final message in grid order.
Card Quote, also called Deck it Out: A blank 13x4 grid representing a deck of cards is provided. 13 words are clued, one for each rank, with blanks for the typically 6-letter answers and suit symbols under 4 of the blanks for each answer to be transferred into the deck in the manner of a double crostic. The deck spells out a final message.
Chess Words: A chessboard is given with letters on each square and the pieces that normally start in rank 1 pictured below the board. You are to form 8 8-letter words starting with the letters on their starting spaces, moving as those pieces move (so the knight makes a partial knight's tour, the king has to go one space at a time, etc.)
Code crosswords, also called Codewords: A cryptogram in the form of a block-style crossword. Where the clue numbers would go are instead cipher numbers in every square. The puzzle is usually a pangram; every letter appears at least once.
Coined Phrases: Somewhat like the lettered dice puzzle in the index, but it uses five coins with naturally just two letters on each one. Clues are provided for some words that can be formed with the letters on the coins, using all the letters at least once. Once you figure out which letters are on each coin, you are to arrange them in some order so that another unclued word can be formed, and if you flip all the coins over but leave them in the same order, yet another unclued word is formed.
Family Reunions: Find sets of 10 words with a common theme. A transdeletion of each word is provided.
Letters from Outside: A 5x5 block-style crossword grid is given, to be filled with letters given outside the grid, one or two for each row, column, and main diagonal, similar to Slide Show.
Overstuffed Sandwiches: Words are provided with one letter missing, but each word has at least two letters which can complete it. The space for the missing letter is divided in two diagonally. Correctly filled, the letters above the diagonal across all the words spell one additional word, and the letters below the diagonal spell another, usually forming a phrase.
Slide Show: A 5x4 grid is given with two letters already entered. The other letters surround the grid, with two outside letters to slide somewhere into each row and two into each column to create a word rectangle.
Syllabism, also called Syllable Saying: Clues are given for longish (typically 8-12 letter) words. The answers are broken up into syllables and all the syllables for all answers are provided in a single alphabetized list.
Word Rummy, also called 500 Rummy: A 13x4 grid is provided already filled in with letters, with row and column labels to represent a deck of cards. You are to form 7-letter words which combine a set of 3 or 4 cards of the same rank (in any suit order) and a run of 3 or 4 consecutive cards in the same suit (used in order in the word). The set and run for a word may not reuse the same card, though the cards are reused in other words. The set and run letters may not be interleaved in the word, but either the set or the run may come first. This puzzle doesn't have any definite answer; you are just challenged to form all the words you can.

Nikoli-style puzzles. There are a LOT of these. I've divided the list into three parts. First, there are these classic types, ones that have been around a long time, used in USPC, puzzle magazines, Grandmaster Puzzles, or other sources where a lot of people have seen them.

Aqre: Shade some cells which form a single orthogonally connected group. Regions with numbers must have that many shaded cells. There cannot be four consecutive shaded cells in any row or column.
Araf, or Aidabeya: A grid contains various numbers. Divide it into regions each containing two numbers so that the area of each region is strictly between (not inclusive) those numbers.
Arrows: A grid is given with a number in each cell. Outside the grid there is an empty cell at each end of each row and column in which you must draw an orthogonal or diagonal arrow pointing into the grid (so only 2 or 3 choices at each place). Each number in the grid must be pointed to by exactly that many arrows.
Castle Wall: Draw a single closed loop from orthogonal connections of empty cells in the grid. Not all cells need be used. Black cells must be outside the loop, while white cells with heavy outlines must be inside it, and gray cells can be inside or out. Numbers with arrows (on cells of either color) inside the number of segments of the loop (connections between cells, not the cells themselves) which lie along the direction indicated by the arrow.
Clouds, Rain Clouds, or Radar: A grid is given with numbers for each row and column telling how many cells have clouds. There may also be clues indicating the presence of cloud sections or the absence of them. Clouds are rectangles (in some versions with rounded corners where segments are given in the grid, similar to Battleships clues), and they never touch, not even diagonally.
Cross the Streams: A combination of Nonograms and Nurikabe. Shade some cells in the grid. The numbers outside the grid are standard Nonograms clues, but ? indicates a group of unknown size, and * indicates an unknown number of groups of any sizes, possibly none. All the shaded cells must be connected orthogonally into a single group, and no 2x2 region can be completely shaded.
Digital Battleships: Circle the fleet in the grid, as in standard Battleships puzzles with no two ships touching, even diagonally. But each cell in the grid has a number, and the clues outside the grid tell the sum of the numbers on ship segments in the grid.
Double Choco: A provided grid has half its cells already shaded gray. Divide the grid into regions, each of which can be split into a gray polyomino and a white polyomino which are congruent (but may be rotated or reflected). If a region contains one or more of the given numbers, each such number tells the area of either like-colored half of the region.
Double Minesweeper: Like regular minesweeper, but empty cells may contain 0, 1, or 2 mines.
Eminent Domain, or Four Winds: A grid is given with numbers in some cells. You must draw horizontal and/or vertical lines from each number so that each empty cell is on exactly one line and each number is connected by lines to that many other cells (besides itself). Lines cannot span two numbers, nor can there be lines not connected to a number. Hukuwall is a cryptic version of this puzzle, where each number is consistently replaced by the same letter.
Futoshiki: A Latin Square puzzle where inequality signs are placed between some orthogonally adjacent pairs of cells to indicate which has the larger number.
Hamle: A grid is given with some numbered cells. Each cell should move in one of the orthogonal directions the number of spaces as its number. The paths can cross in this puzzle, but when the moves are done, the moved cells should not be orthogonally adjacent and the empty cells should all be orthogonally connected.
Hebi-Ichigo: Place numbers in some of the empty cells so they form snakes 5 units long consisting of the numbers 1 to 5 in order, orthogonally connected. Snakes can touch other snakes only diagonally. Each snake's 1 cell is its head, and it is looking in the direction opposite its 2 cell, up to the next shaded cell or the edge of the grid. No other snake parts are allowed to appear in this space. The clues written on shaded cells indicate which numbered snake part is the first one encountered in the direction indicated by the arrow, and before another black cell. If the clue is a 0, if means there is no snake in that space.
Hidato: A numbered path puzzle like the Snake, but all cells are used (no adjacency rule) and diagonal moves are permitted (including crossing over your path diagonally). Compare with Numbrix, which doesn't allow the diagonals.
Hiroimono, or Goishi Hiroi: This is a classical Japanese variation of peg solitaire. Stones are arranged at lattice points. You have to figure out how to remove all the stones, starting at any stone, and proceeding to other stones along lattice lines, and never U-turning; you can go straight or turn left or right to the nearest stone after picking up each stone.
Hundred, or C Notes: A grid is given with a digit in every cell. Place a second digit in some cells (before or after the given digit) to form two-digit numbers so that the sum of each row and column is 100.
Japanese Sums: Shade some cells in the grid and place numbers in the indicated range in all other cells. Numbers cannot repeat in a row or column, but not all numbers will be used in every row or column. The numbers outside the grid give the sums of adjacent groups of numbers in that row or column, in order.
Kanaore: Place one letter in each cell. Each word given below the grid can be found in the grid, starting at the correspondingly numbered cell and making the first step in the direction given by the arrow next to the word, and making subsequent steps in any orthogonal direction, witout reusing the same cell in the same word. The same cell may be used in different words.
Kin-Kon-Kan: Place one diagonal mirror in a cell of each region so that like letter-number pairs outside the grid are connected by orthogonal light beams reflecting off these mirrors, and the number indicates how many mirrors the beam hits. Each mirror must be hit by at least one beam.
Konarupu, or Corner Loop: Draw a single closed loop of orthogonal connections among the given dots. The numbers in some cells tell how many times the loop makes a 90-degree turn at the cell's corners.
Kropki: A Latin square puzzle in which a white dot appears over each boundary between two consecutive numbers, and a black dot if one number is double the other. All possible dots are given, but the dot between 1 and 2 can be either color.
Kurotto: A grid is provided with circles in some cells, and numbers in some circles. Shade some empty cells (cells with circles cannot be shaded). The black cells are divided into orthogonally connected groups. Each number in a circle indicates the total area of the black cell groups which share an edge with it.
Lighthouses: The numbers on black cells in the grid represent lighthouses, which shine on all the squares in its row and column, including through other ships or lighthouses. The number on each lighthouse represents the number of ships it illuminates. You are to locate all the single-cell ships, which do not touch other ships or lighthouses, even diagonally.
Lighthouse Battleships: A combination of Lighthouses with Battleships. The ships are now a given Battleships fleet rather than all occupying single cells, and the numbers are lighthouse clues telling the number of illuminated segments.
Minesweeper Battleships: Locate the given fleet of ships in the grid, which cannot touch, even diagonally, as in standard Battleships puzzles. Clue numbers in the grid are never part of ships and indicate the number of ship segments in the 8 adjacent cells.
Mochikoro: A grid containing numbers in some cells. Like Nurikabe, you are to shade in some of the empty cells to leave each number in a separate "island" of cells the size of that number, and also like Nurikabe, you can't shade all of a 2x2 region. But there can be unnumbered islands in this puzzle, and instead of the black cells all having to be connected, in this puzzle all the white islands have to be diagonally connected.
Nanro, or Number Road: A grid is provided, divided into heavily outlined regions and with numbers in some cells. Add numbers to other cells so that each region has at least one number, the numbers within each region are all the same, and equal the number of numbers in the region, all the numbered cells form a single orthogonally connected region, when numbers are adjacent across a region boundary they are different numbers, and nowhere are there numbers in all cells of a 2x2 region.
Norinori: A grid is divided into heavily outlined regions. Shade in some cells so that every region contains exactly two shaded cells, and each shaded cell is orthogonally adjacent to exactly one other (possibly from a different region).
Number Cross: A grid is provided with numbers in every cell and one number outside each row or column. Shade some of the cells so the numbers outside the grid give the sum of the unshaded numbers in their row or column.
Numbrix: A numbered path puzzle like the Snake, but all cells are used (no adjacency rule). Compare with Hidato, which allows diagonal moves.
Nuraf, or Araf Nurikabe: Shade some unnumbered cells so that the unshaded cells form islands which can only touch diagonally, and with no 2x2 region entirely shaded. Each island must contain exactly two numbers, and the area of the island must lie strictly between (not inclusive) those numbers.
Nurimeizu, or Nurimaze: A grid is provided, divided into heavily outlined regions, and wit circles and triangles in some cells and one S and one G. Shade some entire regions so that there is exactly one path of orthogonally connected cells from S to G. This path must include all circles and no triangles. Additionally, no 2x2 region can be all one color, and all the white cells must be orthogonally connected into a single group.. Cells containing any symbol cannot be shaded.
Oasis, or Oases: A grid is provided with circled numbers in some cells. Shade some empty cells, no two adjacent, and leaving all the unshaded cells connected orthogonally into a single group, but no 2x2 region entire unshaded. Each number tells the number of other numbers you can reach from that number on paths through empty cells.
Pentopia: Shade some empty cells in the grid in the shape of some of the given pentominoes. Those pentominoes cannot touch, not even diagonally. Pentomino shapes cannot repeat, even if rotated or reflected. The arrows in some grid cells show the orthogonal direction(s) where the closest shaded cells are; if there is a tie, all such directions are shown.
Regional Yajilin: A grid is divided into regions, some of which contain a small clue number in the upper left cell. Shade some non-adjacent cells so that the remaining cells can form a single loop, as in Yajilin, but the clues indicate how many cells in the region are shaded (possibly the one with the clue number),
Ripple Effect, or Hakyuu: A grid is divided into polyominoes, with a number in some cells. You must place numbers into all the empty cells so each polyomino of size N has all numbers 1 to N, and so that wherever the same number N appears twice in a row or column, at least N other cells separate them.
Rotator Mosaic: Divide the grid into rotationally symmetric regions, as in Spiral Galaxies, but the dots do not have to be at the center of symmetry. If they are not, there must be a corresponding dot of the same color at the counterpart position.
Round Trip (a different one from the one also called Grand Tour): Draw a loop of orthogonal connections in the grid which may cross itself (both portions going straight through the intersection) but not otherwise overlapping. Numbers outside the grid represent the number of cells crossed by the first straight segment of the loop from that side running along the row or column.
Sashigane: A grid contains some circled numbers, some empty circles, and some triangles. You must divide the grid into L-shaped regions consisting of an elbow in one cell and two straight arms extending from it at right angles. Each circle must be the elbow of a region. If there is a number in the circle, it indicates the total number of cells in the region. Each triangle must be at the end of an arm and pointing at the elbow.
Snake Pit: Divide the grid along grid lines into snaky regions, which contain no 2x2 regions nor touch themselves anywhere, even diagonally. Cells with circles must be at the end of a snake, and cells with Xs cannot be at the end of a snake. Numbers in the grid must be in snakes of that size. Two snakes of the same size cannot touch each other orthogonally.
Spokes: Numbers are given in a lattice, each in a spoke-hub shape with sockets for spokes to connect in 8 directions. You must draw orthogonal and diagonal lines between the spokes so that each number is connected to that number of its 8 neighbors, all hubs are connected into one network, and diagonal spokes do not cross.
Sukazu: Fill a digit into each cell. Within each row, column, and heavily outlined region, the number of instances of each number which appears equals that number.
Sukoro: A grid is provided with numbers in some cells. Place numbers in some of the empty cells so that all the numbered cells form a single orthogonally connected group, two cells with the same number are not orthogonally adjacent, and each number tells the number of its 4 orthogonal neighbors which have numbers.
Tapa-Like Loop: Draw a single loop with orthogonal connections between cells, not going through the cells with clues. Around each cell with numbers, the numbers give the lengths of groups of adjacent cells connected by the loop. If there is more than one number, each represents a separate segment of the loop, though the groups of cells they go through may be adjacent.
Tapa View, or Canal View: Shade some of the empty cells, forming a single orthogonally connected group, and without shading all of any 2x2 region. Each numbered cell tells the total number of shaded cells it can see in the orthogonal directions up to the next unshaded cell in each direction.
Tatamibari: A grid has +, -, and | symbols in some cells. You must divide the grid into rectangles along lattice lines so that each rectangle contains one symbol. + symbols must be in squares, and - and | symbols must be in rectangles that are long in the direction of the line.
Tren: Enclose each number in the grid in a 1x2 or 1x3 rectangle. Each rectangle represents a car which can only move in the long direction, and the number tells how many empty spaces (on one or both ends combined) are available in which it can move.
Yajisan-Kazusan: Some cells in a grid contain a clue consisting of a number and an arrow. Shade some cells, possibly including some of the ones with clues. The shading must follow Japanese crossword rules: Two shaded squares cannot be orthogonally adjacent and the unshaded cells must form a single orthogonally connected group. The clues in unshaded cells must correctly indicate the number of black cells in the direction of the arrow. Clues in shaded cells can be ignored.

These are just the Sudoku variants:

Arrow Sudoku: Some cells have circles, each with an arrow connected through other cells. The number in the circle must be the sum of all the numbers along its arrow.
Battleship Sudoku: Locate the fleet in the grid, following standard Battleships rules using shaded ship sections in the grid and numbers outside the grid. Each segment of the ships in the provided fleet has a number on it. Enter these on the ships in the grid; they may be rotated any way. The numbers in thegrid follow standard Sudoku rules.
Consecutive Sudoku: All pairs of orthogonally adjacent consecutive numbers are marked with a small box over the boundary line. Consecutive Pairs Sudoku is a variation where not all consecutive pairs need tobe marked, and to distinguish it, small circles are used instead of boxes.
Even-Odd Sudoku: In some cells without givens, a circle indicates an odd number while a square indicates an even one.
Greater Than Sudoku: Futoshiki clues combined with Sudoku. Inequality signs appear between adjacent cells indicating which number is larger. Typically these are between all orthogonal pairs within the 3x3 regions and not across the boundaries of those regions.
Isodoku: The grid is drawn as an isometric drawing of a stack of cubes. In place of the usual rows and columns are lines starting at any outside edge and proceeding through opposite edges of the rhombic cells. This generally forces the regions to be irregular.
Kropki Sudoku: Kropki clues combined with Sudoku. White dots appear on boundaries between consecutive numbers and black dots where one number is double the other. All possible dots are given, but the dot between 1 and 2 can be either color.
Little Killer Sudoku: Numbers outside the grid with diagonal arrows indicate the sums of numbers along that line. These sums can include repeated digits.
Minesweeper Sudoku, or Sudoku Mine: The numbers are minesweeper-style clues, not Sudoku fill. Place three mines in unoccupied cells each row, column, and 3x3 region to match the given clues.
Outside Sudoku: Up to three numbers are given at each end of each row and column. Those numbers must appear within the first three numbers from that side.
Outside Sum Sudoku, or Frame Sudoku: Numbers outside the grid give the sum of the first three entries from that side in the row or column.
Rossini Sudoku: An arrow pointing into the grid along a row or column indicates that the first three numbers in that direction are ascending, and one pointing outward indicates the first three numbers are descending. All possible arrows are given.
Sandwich Sudoku: Numbers outside the grid give the sum of all numbers between (not inclusive of) 1 and 9 in that row or column.
Skyscraper Sudoku: Numbers outside the grid give Skyscrapers-style clues indicating how many of the numbers in that row or column can be seen from that end, treating the numbers in the grid as the heights of buildings.
Sudo-Kurve: The regions may be split apart from one another. Bent lines outside the grid connect rows and columns that should be considered part of the same uniqueness group.
Sudoku XV: All boundaries between cells containing two numbers that sum to 10 are marked with an X, and those summing to 5 are marked with a V.
Sujiken: A triangular grid containing half a 9x9 Sudoku grid. In addition to the usual restrictions, no number can be repeated on a diagonal of any length.
Sukaku, or Pencilmark Sudoku: Each cell contains small digits showing all possibilities allowed in the cell.
Star Sudoku: The grid consists of 6 triangular regions each containing 9 triangular cells, with a 6-cell hexagonal hole in the middle. Regions containing each digit once for this puzzle include the large triangles, 9-cell strips crossing the hole, and 9-cell regions on the edge which include 8 cells in a straight line and one cell which is in an adjacent line by itself.
Strimko, or Chain Sudoku: Essentially a variant on Sudoku with irregular regions; in Strimko, the cells are replaced with circles and lines connect the circles that belong to the same region, which may include diagonal connections.
Thermo-Sudoku: Some thermometers are shaded in the grid, with a bulb at one end. The numbers in the thermometer must be in ascending order, with the smallest at the bulb. (Equivalent to restricted versions of Greater Than Sudoku.)
Tight Fit Sudoku: Some cells have a slash. Enter two numbers in these cells so that the smaller number is above the larger. Both numbers coutn as being in the row, column, and region, so the range is larger than the grid size by the number of slashed cells in each of these.
Tile Sudoku: Some cells are in multiple rows and/or columns, but still take a single digit. Many grid patterns are possible,
Tridoku: A triangular grid made of 9 triangles each containing 9 triangular cells. Regions not containing repeated digits in this puzzle include the large triangles, the 9 cells along each edge, the 9 cells in the middle rows which have exactly 9 cells (which are shaded for convenience), and 6-cell strips spanning each pair of large triangles in each of three directions.
Tripod Sudoku: Sudoku with irregular regions where the regions are not given, but all points where three region lines meet are indicated with dots. There are no points where four region lines meet.
Twin Corresponding Sudoku: Two Sudoku grids with givens are provided. The solutions to the two sudokus are functionally equivalent, like a cryptogram (if a 1 appears in a cell in one grid and a 2 in the corresponding cell of the second grid, all 1s in the first grid will correspond with 2s in the second grid).
Vudoku: Shaded Vs connect groups of three adjacent cells in the grid. One number of each V is the sum of the other two.

And these are just all the other Nikoli-style types I know of which haven't been used in Hunt:

Anraikumozaiku, or Unlike Mosaic: A grid is provided with some shaded cells and circles in some other cells. Divide the unshaded cells into rectangular regions so that each region contains one circle. Regions of the same size cannot share an edge.
Airando, or Island, or Mobiriti, or Mobility: Shade some unnumbered cells. The white cells, including the ones with clue numbers, must remain a single orthogonally connected group (island). Each number tells the number of empty cells that can be reached by orthogonal moves, starting from the number, where other numbers and shaded cells block access. In the version called Mobiriti or Mobility, the numbers are circled.
Area Division: A grid is provided in which every cell has a letter or is shaded. Divide the lettered cells into regions so that each region has exactly one of each letter used in the puzzle.
Arofuro, or Arrow Flow: Place an arrow pointing in one of the four orthogonal directions in each empty cell. The same arrow cannot be placed in two orthogonally adjacent cells. By repeatedly following the arrows one cell at a time, starting at any arrow, you must eventually reach one of the given numbers. The number tells how many starting locations lead to it.
Arrow Maze, or Arrow Path: A grid is given with numbers in some cells and an arrow (orthogonal or diagonal) in every cell except the one whose number equals the area of the grid. Number all the squares so you can move sequentially from 1 to N, each move going in the direction of the arrow in the cell it starts from.
Arrow Web: A grid is given with outlined orthogonal or diagonal arrows in every cell. Shade some of the arrows so that every arrow in the grid points to exactly one shaded arrow.
Bodaburokku, or Border Block: Divide the grid into regions along grid lines. All points where three or four lines meet are marked with dots. Every region contains at least one cell with a number, all instances of the same number go into the same region, and all numbersin a region are the same.
Bricks: Fill in numbers from 1 to N, where N is the size of the grid, so each row and column contains each number once. Each 2-cell brick contains an odd number and an even number.
Buraitoraito, or Bright Light: Fill in stars in some empty cells. The number in each black cell tells how many stars can be seen in orthogonal directions from the black cell. Other black cells block the view, but other stars do not.
Chiyotsui: Shade some cells to form orthogonally connected areas. Each area lies in two regions and is mirror-symmetric with respect to the boundary between those regions. Areas may touchother areas only at a corner. It is possible parts of multiple areas lie in the same region. The numbers tell how many cells in their region are shaded; numbered cells may be shaded.
Chocona, or Chocolate: A grid is given divided into heavily outlined regions and with a number in some regions. Shade some rectangular groups of cells (which may cross region boundaries) so that the given number of cells in each region are shaded. The rectangles can touch only diagonally.
Deddoanguru, or Dead Angle: Divide the grid into orthogonally connected regions each containing one black circle. Each black circle represents an eye which can see in orthogonal directions up to the next region boundary in each direction. The number on each eye tells how many cells of its region the eye cannot see.
Detour: Draw a path of orthogonal connections which visits every cell once. The number in a region tells how many times the path turns within that region.
Different Neighbours (not to be confused with Neighbours): Place a number from 1 to 4 in each empty region so that no two regions with the same number touch, even diagonally.
Dominion: Shade some dominoes in unlabeled cells; each shaded cell is orthogonally adjacent to exactly one other shaded cell. Each orthogonally connected group of unshaded cells is an island. Cells with the same label belong to the same island and every island must have a label.
Doppelblock, or Double Block: Shade two cells in each row and column. Place numbers 1 to N-2 (where N is the grid size) in each unshaded cell so that no number is repeated in a row or column. The numbers outside the grid give the sumof the numbers between the blocks in that row or column.
Dosun-Fuwari: A grid is provided, divided into heavily outlined regions, and perhaps with black squares which belong to no region. Place exactly one white circle and one black circle in different cells of each region. White circles represent balloons. They can only be placed at the top of the grid, directly under a black cell, or directly under another balloon. Black cells are iron balls. They can only be placed in the bottom row of the grid, directly above a black cell, or directly above another iron ball.
Dotchi-Loop: Draw a single loop of orthogonal connections which passes through all the white circles and none of the black circles. In each heavily outlined region, the path easier goes turns at every white circle or goes straight through every white circle.
Double Back: Draw a loop of orthogonal segments through every empty cell. It cannot pass through black cells. Each region must be visited exactly twice.
Douieru: Divide the grid into L-shaped regions. Every circle in the grid is at the corner of an L, and every L has one of the given circles. The black circles mean the legs of the L are of different lengths. Double circles mean the legs are the same length. White circles give no information about the lengths
Endorain, or End Line: A grid is given, divided into regions, with numbers in some cells. Draw separate horizontal and vertical lines, with the ends of each line in different regions. Each number tells how many lines end in its region. Every cell must be on exactly one of the lines.
EntryExit: Draw a loop using all the cells in the grid. It can only enter and exit each marked region once.
Eulero: A double Latin square puzzle. Fill in each cell with a number and a letter so that each row and each column contains each number once and each letter once, and each combination of letter and number appears once over the entire puzzle.
Firumatto: A grid has numbers in some cells. Divide it into rectangular regions one cell wide or tall, and one to four cells in the other dimension. Regions may be empty, but each number must be in a region of that size. Two regions of the same size must not share an edge. Four regions cannot meet at a point.
Fobidoshi, or Forbidden Four: The grid contains some circles and some black cells. Place circles in some empty cells so all circles form a single orthogonally connected group, but nowhere are there four circles in consecutive squares of the same row or column.
Foseruzu, or Four Cells: Divide the grid into regions of exactly four cells. The number in each cell tells how many of its edges are region boundaries (including the edge of the whole puzzle). Variations with other sizes are possible.
From 1 to X: Fill in a digit in each empty cell so that each region contains the numbers 1 to X, where X is the area of the region. Two cells with the same number cannot be orthogonally adjacent. The numbers outside the grid give the sum of the numbers in their row or column.
Furisuri, or Free Three: A grid with circles in some cells is provided. Enclose each circle in a separate block of three cells, which may be straight or bent. Some space is left unused. Each block must be able to slide by one unit using the free space.
Gaidoaro, or Guide Arrow: Shade some empty cells, no two of them adjacent, and leaving the unshaded cells as a single orthogonally connected group. There should only be one path (without backtracking) from each arrow to the single star and the direction of each arrow tells where that path starts.
Gappy: Two cells in each row and each column must be shaded. Shaded cells do not touch, even diagonally. The clues indicate the number of cells between the two shaded cells in that row or column. Equivalent to a special case of Hamusando in which there is enough ham to fill all the non-bread cells.
Geradeweg: Draw a single loop of orthogonal connections between cells which passes through all the circles. If the path goes straight through a numbered circle, the number indicates the length of that straight segment. If the path turns at a numbered circle, the straight segments on each side of the turn must be the same length, and this length matches the number.
Golem Grad: Shade some snakes in the grid (paths connecting two and including of the given circles). Snakes cannot cross, and no 2x2 region can be entirely shaded. Orthogonally connected unshaded regions are islands. Islands may contain at most one number, and if there is one it tells the area of the island.
Grades: Place digits 1 to 9 in some cells of the grid, no two of them touching, even diagonally. The numbers at the top and left tell how many numbers are in each row and column. The ones at the bottom and right give the sums of those numbers.
Gyokuseki, or Gems and Stones: Black one black circle in each row and column, and white circles so that each number outside the grid tells how many circles can be seen in that row or column up toand including the black circle.
Hakoiri: Place circles, triangles, and squares in some empty cells so all the cells with shapes are in one orthogonally connected group, like shapes are never adjacent, even diagonally, and each region contains one of each shape.
Hamusando, or Ham Sandwich: Place two squares (bread) and the specified number of circles (ham) into each row and column of the grid. The numbers outside the grid tell how many of the circles are between the squares in that row or column.
Hanare: A grid is given divided into regions, some of them with a number in them. Place a number in some cell of each empty region, always equal to the area of that region. Wherever two numbers are in the same row or column with no other intervening numbers, the number of blank cells between them must equal the difference between the two numbers.
Heki: Divide the grid into regions of exactly 6 cells. Each number tells how many of the orthogonally adjacent cells are in the same region with it.
Hotaru Beam: A grid is given with circles at lattice points. Each circle has an adjacent dot on one of the lattice lines. You must draw a path along the lattice lines from each dot to an edge of one of the circles without a dot. The paths may turn but not touch or intersect. Some circles have a number; the path you draw from that circle's dot must turn that many times.
Ichimaga: Connect all circles into a single network by drawing lines along the grid lines. The line between any two circles may turn at most once. Each circle must be connected to the number of other circles indicated by its number. Lines cannot cross other lines.
Irasuto, or Illustration: Shade some empty cells so that each number in a white cell tells how many empty white cells can be seen in orthogonal directions from that cell, and each number in a black cell tells how many empty black cells can be seen. Numbered cells and cells of the other color block the view.
Irupu, or I-Loop: A grid is given with circles in some cells. Place 1x3 blocks horizontally or vertically so that there is one covering each circle, they all form an orthogonally connected group, and each block touches two others orthogonally. (These rules require the blocks to form a loop.)
Jemini: Divide the grid into regions, each containing exactly one given letter. Regions of the same shape and orientation must have the same letter in the same position. All instances of the same letter are in regions of the same shape and orientation.
Kabingurodo, or Curving Road: A grid is provided with some cells having circles. Shade some empty cells, no two orthogonally adjacent, leaving all unshaded cells (including the circles) in one orthogonally connected group, so that each path from a circle to any other circle requires at least two turns.
Kaero, or Ouchihekaero: Move some of the given letters along paths of orthogonal segments, so that all the letters that end up in the same region are the same letter. paths of moving letters cannot cross other letters or paths.
Kanjo: Draw a set of looping paths which go through all grid cells, including the ones with numbers, and using all the given fragments. Each loop contains all instances of one number, and different numbers are on different loops. Loops can cross themselves or each other by passing through in perpendicular directions. Loops cannot cross in cells with numbers.
Kapama, or Sunglasses: Shade some empty cells of the grid to form pairs of mirror image shapes. These shapes cannot touch their mirror images or other shapes except at corners. Each mirror image pair must be connected by one of the given diagonal lines, which must lie perpendicular to the line of symmetry. The numbers outside the grid tell the number of shaded cells in each row or column. In theSunglasses variant, the connecting lines may be in other shapes besides a diagonal line through a single cell, but they must still be bisected by the line of symmetry.
Kapetto, or Set Carpets: Divide the grid into rectangular blocks each containing one number, which is the area of the block. Some cells may belong to no block. (Essentially the same as Shikaku except for some cells being part of no block).
Knossos: Divide the grid into regions along the cell boundaries so that each region contains one given number, which is the total length of the region's boundary.
Koburin: Shade some empty cells so that each numbered cell is orthogonally adjacent to that many shaded cells, and so that a loop made of orthogonal segments can be drawn through all unshaded, unnumbered cells. Shaded cells cannot be orthogonally adjacent to other shaded cells. Some shaded cells may not be adjacent to numbers.
Kohi Gyunyu, or Coffee Milk: A grid contains white, gray, and black circles. Connect the circles with horizontal and vertical lines which do not intersect except at circles. Each group of circles connected by lines must contain one gray circle and equal amounts of white and black circles. Lines may not directly connect white and black circles.
Kojun: Fill numbers into the empty cells so each region contains the numbers 1 to N, where N is the size of the region. Orthogonally adjacent numbers must be different. Wherever two numbers are vertically adjacent and in the same region, the upper one must be greater than the lower.
Korekutokonekuto, or Correct Connection: Black and white circles are given at lattice points, some white circles containing numbers. Connect white circles with horizontal and vertical lines, without crossing other lines or black circles, so that all white circles are in a single connected network, the number of connections to each numbered circle matches the number.
Kuroclone: Shade some cells, forming two orthogonally connected groups in each region which are of the same size and shape (but they may be rotated or reflected). Shaded cells are never orthogonally adjacent to shaded cells in other regions. The arrow-and-number clues indicate that the next cell in the direction of the arrow is part of a group of the indicated size. Cells containing clues are never shaded.
Kuroshiro, or Black and White Loop: A grid is given with black or white circles in many cells. Draw a loop using orthogonal connections through all cells. When two consecutive circles along the loop are the same color, the loop must not turn between them. When the circles are of different colors, the loop must turn exactly once between them.
Kuroshuto: Shade some empty cells, no two of them adjacent, and leaving all the white cells (including ones with clue numbers) orthogonallyconnected. Each cell with a clue numbers requires exactly one other cell orthogonally that distance away is shaded.
Light and Shadow: A grid is given, with some shaded cells and numbers given in both white and shaded cells. Shade additional cells so that each orthogonally connected region of the same color has exactly one number and that number equals the area of the region.
Line Segment: Draw line segments through groups of 3 or 4 orthogonal or diagonal cells, so that every cell has exactly one segment. Diagonal segments may cross other diagonals at lattice points, but otherwise the segments may not cross. The cells with H, V, or D in the grid must be crossed respectively by horizontal, vertical, or diagonal segments.
Linesweeper: Draw a single closed loop by connecting orthogonally adjacent empty cells. The numbers in some cells are Minesweeper-style clues, telling how many of the 8 neighboring cells are part of the loop.
Makaro: A grid is provided which is divided into regions with heavy bars, with numbers in some cells, and some blacked-in squares, some of which have an arrow pointing in one of the orthogonal directions. Fill in numbers in all empty cells so that each region of size N contains the numbers 1 to N once each. Among the (up to) four neighbors of a cell with an arrow, the one pointed to by the arrow must be larger than any other. Identical numbers cannot be orthogonally adjacent.
Masakuchi: A variant of Makaro in which the cells with arrows also contain a number. The number gives the difference between the largest and second-largest neighboring numbers.
Mathrax: A Latin square puzzle. Circles containing clues appear at some intersections. If the clue is E, all four cells meeting there must be even; if O, all odd; and if a number and an operation, each pair of cells on a diagonal from the clue, when the given operation is applied, produces the given number.
Meadows: Divide the grid along grid lines into square regions, so each region contains one circle. Equivalent to Tatamibari with only + clues.
Meandering Numbers, Count Number, or Worms (but see Wamuzu, which is also called Worms): Fill in digits in each cell so that each region contains the numbers 1 to N in order in an orthogonally connected path. Two cells with the same number cannot tough, even diagonally.
Mid-Loop: Draw a loop of orthogonal lines between cell centers which passes through all the given dots (which may appear in cell centers or on the lines between cells) and never turns at a dot. Each dot must be at the midpoint of the straight segment of the loop containing it.
Mintonette: In an irregular grid with circles in some cells, some of them numbered, draw paths of orthogonal segments through every cell. Each path starts and ends in cells with circles, and crosses no other circles or paths. If either circle at an end of a path contains a number, the path must make that many turns.
Mirukuti, or Milk Tea: Connect groups of three circles (two white and one black) with T-shaped lines, so that the two white circles are connected by the straight part of the T and the black one is on the perpendicular segment. Lines cannot intersect except to form the Ts.
Miti: Draw roads along the cell boundaries, so that all the cells of the grid form a closed loop with no sections wider than a single cell. At each given dot, exactly three roads must meet, and at every other intersection only one or two road segments can be used.
Mobunanba, or Move Number: Mark a block of three cells (straight or bent) enclosing each given number. Some cells will be unused. The number tells in how many of the four orthogonal directions that block can be moved into unused cells.
Nanbaboru, or Number Ball: A grid is given with numbers in some cells, circles in others, and Xs in still others, along with a given range of numbers. Place numbers in some of the empty cells, and all of the circles, and none of the Xs, so that each number appears once in each row and column.
Nawabari, or Territory: Divide the grid into rectangular regions so that exactly one given number is in each region. The number tells how many of the four sides of that cell are on the boundary of the region, including the edge of the grid.
Neibadomino, or Neighbour Domino: Mark dominoes (1x2 regions) in the grid. Some cells may be unused, but all the given numbers indicate how many other dominoes share an edge with that domino. Dominoes with the same number of neighbors cannot share an edge. Dominoes may use 0, 1, or 2 of the given numbers. Dominoes cannot cover all of any 2x2 region. (But there can be empty 2x2 regions and the dominoes do not all have to connect orthogonally.)
Neighbours: A grid (possibly of irregular shape) is to be divided into regions. Each region must contain exactly one clue number or question mark. If it contains a number, the number indicates how many other regions share one or more units of boundary with the region.
Nondango: A grid is given divided into regions, with circles in some cells. Shade one circle in each region, so that circles of the same color never appear in a three consecutive cells of any row, column, or diagonal.
Number Chain: A grid is provided containing numbers from 1 to some maximum N. Draw a path of orthogonal connections from the top left to the bottom right cell which uses each number once (in any order).
Nuribou: Shade some empty cells in rectangles one cell wide or tall. which can touch only at corners and only if the sizes of the black strips are different. The orthogonally connected groups of white cells must each contain one number which gives its size, like in Nurikabe.
Nurimisaki: Shade some empty cells. No 2x2 region can be all the same color. The white cells form a set of interconnected paths. Cells with circles are at the end of a path (only one white orthogonal neighbor) and other white cells must NOT be at the ends of paths. If a circle has a number, it means you can see that many cells from it (including the cell itself, and all in one line since the circled cell has only one white neighbor.)
Patchwork, or Tatami (not to be confused with Tatamibari): A grid is divided into regions of the same size. Each region should be filled with the numbers 1 to N, where N is the size of the region. Adjacent cells must not contain the same digit, and each row and column must contain each digit the same number of times.
Peintoeria, or Paint Area: A grid is divided into heavily outlined regions and many of the cells have numbers from 0 to 4. Shade all the cells in some of the regions (including cells with numbers) so that out of the 4 cells orthogonally adjacent to each numbered cell, the number indicates how many are shaded, no 2x2 region is all the same color, and all shaded cells are in a single orthogonally connected group.
Pencils: A grid (with dashed lines) has numbers in some cells and pencil tips in others. Draw pencils in the grid consisting of a 1xN rectangle with a pencil tip against a short end. In addition, draw a line of orthogonal segments of the same length as the pencil ending at each tip. Each number must be in the rectangle of a pencil of that length, each given tip must be attached to a pencil, and each empty cell must be part of exactly one pencil or line.
Pipelink: A grid is given with straight, bent, or crossover pipe segments in some cells. Fill in every empty cell with one of these pipe types so all the pipes form a single loop.
Rabbits and Trees, or Raitonanba: Place one white circle (representing a rabbit) and one black circle (representing a tree) in empty cells in every row and every column of a grid, so that each clue number tells how many rabbits can be seen in orthogonal directions from that cell. Rabbits behind trees cannot be seen
Raneko: Divide the white cells into regions which each contain one circle. If the circle has a number, it tells the size of its region. The black cells are not part of any region; a black cell with a number tells how many regions share an edge with it.
Rectslider: A grid is given with some black cells, some of them numbered. Slide some of them horizontally or vertically so that the black cells all form rectangles of two or more cells which do not touch orthogonally. The paths of sliding black cells cannot cross. Black cells with numbers must move the distance indicated by the number.
Renkatsu: Divide the grid into orthogonally connected regions so that each region contains numbers from 1 to N once each, where N is the size of that region.
Rekuto: Divide the grid into rectangular regions each containing one given number, which equals the sum of the width and height of its region.
Renban: Fill a number into every empty cell so that the numbers in each heavily outlined region form a set of consecutive numbers, which may appear in any order, and each row and column of the puzzle contains every number from 1 to N once, where N is the size of the grid.
Rimotoejji, or Remote Edge: Connect all dots with a single loop of orthogonal segments. All the arrows and Xs must be inside the loop. Each arrow points in the direction of the longest straight path of cells inside the loop starting at that cell. Each X has two or more directions tied for the longest such path.
Roma: A grid is provided, divided into regions with heavy bars, with a circle in one cell and arrows pointing in orthogonal directions in some others. Place an arrow into every empty cell so each region does not contain two arrows pointing in the same direction, and if you follow a path moving in the direction of the arrows starting from anywhere, it ends at the circle.
Rukkuea: Shade some square regions of cells, possibly including the given numbers. These square regions can touch only diagonally. In any row or column containing parts of two shaded regions of the same size, there must be a shaded region of another size between them. Each number tells how many of five cells (the cell itself and its four orthogonal neighbors) are shaded.
Santoitchi: Shade some of the empty grid cells, no two of them orthogonally adjacent. Divide the remaining cells into regions of size three, which may be straight or bent, and each containing one of the given numbers, which indicates the number of black cells the region shares an edge with..
Sashikabe: Sashigane combined with Nurikabe. All the islands must be L-shaped and one cell wide, as in Sashigane. Circles must be at the bends of islands and arrows at the ends, pointing at the bend. If a number is in a circle, its island must contain exactly that many cells. As in Nurikabe, islands can only touch diagonally, all black (non-island) cells must be connected orthogonally in a single group, and no 2x2 region of all black cells may appear. Islands don't have to contain clues.
Sashikaku: Divide the grid into rectangular regions with one number in each. The number tells the difference between the width and height of the region.
Satogaeri, or Coming Home: A grid is provided divided into regions with heavy bars, with circles in some cells and numbers in some circles. You must move some circles vertically or horizontally (not both) so that each region contains only one circle. If the circle has a number, it must move exactly that many spaces; circles with 0 cannot move and empty circles may move or stay where they are. The paths of moving circles (including their start and end spaces) may not intersect.
Scrin, or Screen: Draw rectangular regions in the grid which touch only at corners, and only so that they form a single closed loop. Each circle must be in one of the regions and if the circle has a number, it specifies the area of the region.
Seethrough, Doors, or Open Office: Each cell in the grid represents a room in an office, initially with gaps in every wall between rooms which represent doors. You are to close some doors so that each number indicates the number of other rooms (not including the cell itself) you can see from that room, looking in orthogonal directions through open doors. Compare with Corral.
Shimaguni: In each region, shade a single orthogonally connected group of cells. If the region has a number, that many cells must be shaded. Regions sharing one or more units of edge must have different numbers of black cells. Black cells in different regions cannot be adjacent.
Shingoki: Draw a closed loop of orthogonal segments which passes through all given circles. The loop must turn at black circles and go straight at white circles. Gray circles have no restriction on turning. If a circle has a number, it tells the sum of the lengths of the straight segments on both sides of the circle, including distance beyond one or more circles if the loop goes straight through them.
Shirokuro: Connect each white circle to a black circle using a horizontal or vertical line. Each circle may have only one line and the lines cannot cross other lines or circles.
Sign In: + and - signs appear between some pairs of orthogonally adjacent cells. Fill in numbers from 1 to N, where N is the size of the grid, so each row and column contains each number once, and a - indicates the number above or to the left is one less than the number below or to the right, and a + indicates the number below or to the right is one less than the number above or to the left. All possible instances of these clues are given. Compare with Futoshiki and Kropki.
Slash Pack: An irregularly shaped grid contains froms from 1 to N in some cells. Draw diagonal lines through some cells, never intersecting within a cell, to divide the grid into regions containing each number exactly once.
SquarO: A grid is given with circles at all lattice points (including on the edges) and numbers in the cells. Fill in some circles so each number tells how many of the 4 dots at its corners are filled.
Starry Night: Place one star, one sun (white circle), and one moon (black circle) in each row and column. The clues outside the grid relate to where the star is in the row or column. If the clue is a sun or moon, it means that symbol is closer to the star. If the star is outside the grid, it is the same distance from the sun and moon.
Stars and Arrows: Place stars in empty cells so each arrow points at exactly one star and each star is pointed at by exactly one arrow, and the numbers outside the grid tell the number of stars in each row and column.
Stitches: Add some stitches to the grid (nonoverlapping orthogonal lines connecting two adjacent cells in different regions) so each region is connected to each of its neighboring regions exactly once each. Numbers outside the grid tell how many cells in the row or column have stitch-ends in them.
Stostone: Shade some cells, forming an orthogonally connected group within each region and without orthogonal connections to shaded cells in other regions. At least one cell must be shaded in each region; if the region has a number, that many cells must be shaded. Treating each group of shaded cells as a stone, if the stones fall down, they will exactly cover the bottom half of the grid.
Straights, or Str8ts: Fill each empty white cell with a digit from 1 to 9, so that no digit repeats in a row or column. Some cells in the grid are shaded and these break the rows and columns into crossword entries. Each crossword entry must be a "straight," a group of consecutive digits, which may be out of order, such as 5-7-6 or 4-1-3-2. Some black cells may contain numbers, which block that number from the row and column but are not part of any straight. Compare with Sutoreto.
Suguru, or Number Blocks: Place a number in each empty cell so that each heavily outlined region contains all the numbers from 1 to N, where N is the size of the region. Two cells with the same number cannot touch, even diagonally.
Sukima: A grid is provided with some shaded cells and circles in other cells. Mark a region of area 3 (may be straight or bent) covering each circle and not using any shaded cell. Other cells besides the shaded ones will also remain unused. No 2x2 region can be completely covered with marked regions.
Sukrokuro: Combines some elements of kakuro, sudoku, and kropki. Fill in digits 1 to 9 in empty cells so that numbers given for each crossword entry match the sum of its digits, and so that each row and column contains the digits 1 to 9 once each. Additionally, wherever a white dot appears between two cells, their numbers must be consecutive, and where such dots do not appear, the numbers must not be consecutive.
Sun and Moon (not to be confused with Moon-or-Sun), also called Munraito: Some planets are given in some cells of the grid which may be illuminated on some quadrants. Place one star and one cloud into each row and column of the grid. Stars illuminate horizontally and vertically to the first star or cloud in each direction. The illumination on thegiven planets must match that provided by the stars.
Suraromu: Make a loop through some of the white squares in the grid, exactly one square from each gate (indicated with a dashed line), and the circled number, which represents the start of the loop and, for convenience, tells you the total number of gates in the puzzle. Some gates are numbered, by printing a white number on the black cell(s) at one or both ends of the gate. The numbers indicate the position in the sequence of gates traversed which that gate must occupy.
Sutoreto: The given black squares divide the rows and columns into crossword entries. Fill in a digit in each empty cell so that the numbers in each crossword entry form a set of consecutive digits which may be out of order, such as 5-7-6 or 4-1-3-2. Compare with Straights.
Tairupeinto, Tile Paint, or Crazy Pavement: A grid is provided, divided into heavily outlined regions. Shade some of those regions entirely so the numbers outside thegrid give the number of shaded cells in each row and column.
Tasukuea: Shade some cells forming square regions. The cells with clues cannot be shaded. Clue numbers indicate the total size of the shaded squares which share an edge with it. Question mark clues must be next to at least one shaded cell. All unshaded cells (including cells with clues) must form a single orthogonally connected group.
Tenner Grid, From 1 to 10, Zehnergitter, or Grid Ten: A grid 10 cells wide is given, with digits in some cells. Fill the unshaded cells with digits so each digit from 0 to 9 appears once in each row, the numbers in each column sum to the number given at the bottom, and the same digit doesn't appear in adjacent cells (even diagonally).
Tents: A grid is given with trees in some cells. You must place a tent orthogonally adjacent to and connected to each tree. Tents cannot touch, even diagonally. Tents may touch other trees besides the one they are connected to. The number of tents in each row and column is given.
Tetoron: Divide the grid into regions of exactly four cells, with exactly two symbols in each region and those two symbols must be different. Regions of the same shape (including rotations and reflections of that shape) must contain the same two symbols.
Tetroid: A grid is given with some shaded cells. Divide the unshaded cells into tetrominoes (L, I, T, S, O). Two tetrominoes of the same type cannot share an edge.
Terra X, Terra XV, Terra XX: A grid is given divided into regions, with a number in some regions. Place a digit 0 to 9 into each empty region, so that at each place where four regions meet at a point (marked with a dot) the numbers in the four regions sum to 10 for Terra X, 15 for Terra XV, and 20 for Terra XX.
Toichika: Place arrows pointing in orthogonal directions in some empty cells so each region contains one arrow, all arrows are in pairs that point at each other with no other arrow between them. and two regions with paired arrows do not share an edge.
Trace Numbers: Draw a set of paths which collectively visit every cell. Each path starts at a cell numbered 1, and proceeds through the other numbers consecutively, ending in one of the cells with the largest number.
Trilogy: Fill in a square, circle, or triangle in each empty cell so that no group of three consecutive symbols in a row, column, or diagonal is all the same or all different.
Trinairo: Fill each empty cell with A, B, or C. Each row and column must have the same number of As, Bs, and Cs. Shaded cells are different from all their orthogonal neighbors.
Trinudo: Divide the grid into regions of size 1, 2, or 3. Each given number must be in a region of the indicated size; a region can have no number or more than one. Regions of the same size cannot touch along an edge.
Triplets, or One or All: A grid is provided divided into regions of area 3, with symbols (circles, squares, or triangles) in some cells. Place these symbols in every empty cell so that each region contains either all the same symbol or all different, and when symbols are adjacent over a region boundary the symbols are different.
Turf: Shade some cells to divide the grid into shaded and unshaded, orthogonally connected regions. Each region must contain a number equal to the size of the region. The region may contain cells with other numbers; these numbers must equal the number of white cells adjacent to cell, including diagonals and the cell itself.
Usotatami: Divide the grid into regions one cell wide or tall and of any size in the other direction, so that each region contains exactly one given number, and that number is NOT equal to the size of the region. Four regions cannot meet at a point.
Usowan: Shade in some empty cells, never two orthogonally adjacent ones, so that the unshaded cells (including ones with clues) form a single orthogonally connected region. The clue numbers say how many of the (up to four) orthogonally adjacent cells are shaded, but in each region there is one clue that is wrong.
Walls: Similar to Eminent Domain, but some cells may have walls that don't connect to a clue number, and some walls may connect two clue numbers in the same row or column and count toward both.
Wamuzu, or Worms (but see also Meandering Numbers which is also called by this name): Connect circles in pairs with paths of orthogonal connections which make a right-angled turn at every step. Every cell must be part of one of the paths.
Water Fun: Shade some cells of the grid so that the clues outside the grid tell the number of shaded cells in their row or column. Wherever a cell is shaded, all other cells in the same region at the same or lower height must also be shaded (so each region has a "water level").
Yagit, or Goat and Wolf: A grid is provided with circles (goats) in some cells, squares (wolves) in others, and dots at some lattice points. Add some fences along grid lines, from one spot on the edge to another. Fences may turn only at the given dots. Fences may cross each other anywhere other than the dots. Each region set off by these fences must contain wolves or goats, but not both; regions may not be empty.
Yajikabe: Yajilin combined with Nurikabe. Clues in the grid with arrows cannot be shaded and tell the number of shaded cells in that direction, to the edge of the grid. All shaded cells for an orthogonally connected group and there cannot be a 2x2 region entirely shaded. There is no restriction on the number of clues in an island.
Yajisan-Sokoban: Move some of the given gray squares in paths which do not cross other paths or gray squares; they may cross over the numbers. Each number tells how many gray squares end up in the direction of its arrow. However, if a gray square ends on top of a number, it negates that clue and the number may or may not be correct. Numbers which have been crossed over but not stopped on by squares remain valid.
Yokibunkatsu: Divide the grid into regions of five cells, each containing exactly one star, such that they could be folded into open boxes, with the star on the bottom and an open top. Some boundary segments may be already given. There may also be empty regions with no star, which are unrestricted.
Yonmasu: A grid contains some shaded cells and some circles. Divide the unshaded cells into regions containing exactly four cells each including one circle.
Yunikumaka: Divide the unshaded cells into regions of exactly four cells, containing exactly one dot in its interior. Region boundaries may pass through dots and those dots are ignored and not considered part of any region.