My school uses NBME... I do around 300-400 practice questions before every exam (we have 1 exam per block). They provide us with about 100 of those practice questions throughout the block, and the rest come from ScholarRX, Amboss, Osmosis and the BnB quizzes. I love it. My class got a massive discount for Amboss, and we were provided ScholarRX and Osmosis with the school, so I can’t speak to whether or not it’s worth it to buy it yourself. I rely heavily on practice problems and have scored very well. I personally am saving UWorld for STEP prep but with P/F Step 1 for my class (most likely), I’m not sure how much it matters. Anki to reinforce everything!