This app looks pretty good. There's also RemNote [1] which serves a similar function. It's kind of like Roam + Anki all in one.

I'm really loving the proliferation of good new ideas for note-taking and memorization. I wish I had some of these tools when I was in school. Even if some of them are paid right now, it's only a matter of time before solid free and open-source competition emerges. I'd love to see some Anki-like tools for Athens [2].

[1] https://www.remnote.io/pricing/feature_chart [2] https://github.com/athensresearch/athens