I've found this one for free on steam, and apparently it's been mentioned here a few times.
https://store.steampowered.com/app/3350140/GO/
Then I brought this one for 3 US dollars, Phantom Typer and I think it's pretty good as well, once you change the settings
https://store.steampowered.com/app/1439010/Phantom_Typist/
Does anyone know any others that are good? Kanji quizzing with dopamine, even if it's not the most effective.
by Harly16