Logic Wiz Sudoku & Variations FREE

 

Logic Wiz Sudoku & Variations has a wide variety of sudoku versions.

Each version comes with many levels in beginner, easy, moderate, hard mode.

My favorite version is Sandwich Sudoku.

It's free, comes with ads, but is very well done.   

https://apps.apple.com/us/app/logic-wiz-sudoku-variations/id1530683853