There are several subjects under history and social sciences students are usually able to self study if the goal is to run up the score of number of APs taken. Psychology is pretty easy is what I have heard although college level is considered not so easy. many take european history as self study when they take world history in school in our local school. I advise kids to aim for national AP scholar award by the time they are applying to colleges [8 APs with at least 4] if they want to be academically competitive for top schools since this is not an easily reachable distinction at the end of 11th and makes them noticed. Doing 8 APs in senior does not have the same impact since no one knows the outcome while applying.
I cant say much about whether any of this helps BS/MD applications but this goal has helped both my children get into some of toughest to get into undergrad colleges.