I probably won't read YA now that I'm away from the library and don't know what's popular and being required. We had an entire section devoted to YA, which shows how important they've become.
YA deals with a broad range of subjects: of course, the usual teen problems, but also with being a refuge (Alan Gratz, Refuge, which is one I was impressed with); environmental issues; parent being in prisoned (in fact, we had a J(uvenile) on that topic also; being a black person and the problems; being a brown person and the problems; being a teen mother; death of a parent or grandparent (also J books on those subjects); as well as a lot of fantasy stuff. John Grisham has a Kid Lawyer series. In other words, most of the topics adult books are written on.
I was impressed by the diversity of topics. Alan Gratz had an extremely popular one, Prisoner B-3087 dealing with being a prisoner in a Nazi concentration camp. That one also impressed me.
I mentioned The Librarian of Auschwitz, dull in places but overall impressive that a youngster could survive such risks.