Spaced repetition system
Should be a popup where you can flip through flashcards quickly. The suggestion to use repeated tasks is nowhere near good enough, very impractical https://www.amplenote.com/help/spaced_repetition_learning_use_case
Maybe a plugin could read through all pages with a certain tag, like #spaced-repetition, where it interprets all top-level bullet points as Questions and whatever is indented below them as their Answer (hidden in review until the card is flipped)
The metadata about when a card should show next, and its value for how well you remember it, could maybe be in a json string in an additional nested bullet point, which is hidden in the flashcard mode?
It doesn't need to be very advanced. A simple solution goes a long way.
That said, stacks (categories) for flashcards would be great