I recently built Cranki [0], a free little PWA that generates crosswords using your Anki flashcard lists. It's aimed at language learners (who find flashcards boring and crossword fun!). To be honest I built it just for me and then decided it might be useful for others.

It's all local, no server, no database, etc. Mobile and desktop friendly.

I did build it with the help of AI, but no AI inside the actual thing.

[0] https://cranki.app