I like RemNote [1] because of its native flashcards feature (besides its top-notch note-taking functionalities). It allows you to turn your notes into flashcards and practice them using spaced repetition algorithm. Ren's video [2] is a great intro to RemNote
Just want to complain that I bought Dash 2, and there's no way to access it after the Dash 3 is out. I don't understand why the guy wants to make money this way. Good job Apple.
[1] https://www.remnote.io/
[2] https://youtu.be/M2U61vHfQSQ