I really enjoy the Fantasic Beasts + The Crimes of Grindelwald a lot because they are well-made and add a lot of background info to the original world of Harry Potter. Grindelwald gets fleshed out and the world before Voldemort's entrance is built and built well. I love it!

I also love The Tales of Beedle the Bard because the stories in that little thing also adds to the original Harry Potter world. I listened to it just recently and enjoyed it a lot!