SudoKanard

Arrow/Thermo/Quadruples Sudoku "400 subs"     Standard Sudoku rules apply. Digits strictly increase along each thermometer starting from the bulb end. The digit in a circle is the sum of all digits along the arrow attached to the circle. When a circle overlaps four cells, the digits in the circle must appear at least once in the four cells.   This puzzle celebrates 400 subscribers to the YouTube channel SudoKanard.   Solve this puzzle on SudokuPad:  https://tinyurl.com/2be2y54h

 Quadruple Sudoku Standard Sudoku rules apply. Digits in a circle must appear at least once in the surrounding four cells. Solve on Penpa: https://tinyurl.com/yxuobgtg Solve on SudokuPad: https://tinyurl.com/36v2ypwu

 Between Quadruple Sudoku Standard Sudoku rules apply. Digits in a small circle must appear at least once in the surrounding four cells. Digits on a gray line must lie strictly between the digits in the grey circles at the ends of the line. Solve on Penpa: https://tinyurl.com/y8fy62ug Solve on CtC:  https://bit.ly/3NlIS4A