I have not used many of these websites before. If anyone has and has good/bad experiences to share as well as any other sources for books, please do!
I would also just like to warn everyone that, since the course hierarchy is program material, BOS, school-issued resources, and then internet sources, it would be recommended to check anything against the course or school resources, especially on your tests and exams.
Sometimes Wikipedia will have a little sound icon for a recording to help with pronunciation. I also used to use YouTube as a student. I would just type in disease/condition names and would often find videos of doctors explaining things online. This can be helpful to “prime” your ear before listening to chapter dictations.