SudoKanard

X-Sums Sudoku Standard Sudoku rules apply. Each clue outside the grid indicates the sum of the first X numbers placed in the corresponding direction, where X is equal to the first number placed in that direction. Penpa link: https://tinyurl.com/2yg7v7au SudokuPad link: https://shorturl.at/swH19

 Next to Nine Sudoku Classic Sudoku rules apply. Digits outside the grid, when given, are the complete list of digits adjacent to digit 9 in the corresponding row/column. Digits are given in increasing order regardless of the order they appear in the corresponding direction. Penpa link: https://tinyurl.com/2lgek6na

  Antiknight Sudoku Standard Sudoku rules apply. Any two cells separated by a chess knight's move must contain different digits. Penpa link: https://tinyurl.com/2ptmqtsf

 Killer Sudoku Standard Sudoku rules apply. Also, the sum of the digits in each cage must equal the value given in the upper-left corner of that cage. Digits cannot repeat inside a cage.   Penpa link:  https://git.io/Juki6

 Yajilin     Blacken some white cells and then draw a single closed loop (without intersections or crossings) through all remaining white cells. Blackened cells cannot share an edge with each other. Some cells are outlined and in gray and cannot be part of the loop. Numbered arrows in such cells indicate the total number of blackened cells that exist in that direction in the grid.   Penpa link:  https://tinyurl.com/2k2vnh4d