Ask HN: Any good apps to take advantage of the forgetting curve?

I just came across this article [0] about the forgetting curve.

I have tried to install Anki[1] for Android but it seems its installs have been blocked on the play store.

I have an android phone, what apps do you use/recommend?

[0]: https://harrisonlo.medium.com/hacking-the-forgetting-curve-1798197b648e

[2]: https://apps.ankiweb.net/