Sudoku is one of the best-selling books on Amazon KDP. There are a variety of different types of Sudoku to choose from, so there’s no end to the number of books you can create. You can also adjust the difficulty to make books for kids or for adults. This gives you a ton of options for book ideas and variations.
My top free sudoku puzzle generator is OpenSky.
If you want to create a large amount of different puzzles, you should try out the Puzzle Generator for Powerpoint. It has 25 different puzzles that it can create along with a bunch of tools to help you create the perfect PDF for KDP.
