I’ve had a lot of fun with this site which quizzes you on tricky kanji:
[https://www.gamedesign.jp/sp/kanji/](https://www.gamedesign.jp/sp/kanji/)
It’s very barebones – type in hiragana and if it matches you get automatically marked correct (you can type in as many different things as you like before the time limit). Every 5 correct answers clears a level. There are supposedly 5 levels total – I’ve gotten to level 5 a number of times but never cleared it.
I hope some of the other people here who enjoy learning new kanji find this interesting too!