[clankyclanker]

That feels like a really broad question. I always find it useful to look up the reading lists for university courses on subjects I’m interested in. You can usually find the PDFs with a quick search in Google Scholar. Then, using something like Polar, you can annotate the readings and directly save your annotations as Anki cards.

That way, you can build a knowledge base of what actually interests you, which you’re much more likely to study and retain in the first place.