3. Harry Potter
If there is one thing I've learned from reading Harry Potter fan fiction, there's never enough stories to tell in the HP universe. Regardless if it's about Harry or not, you can jump to the past and/or to the future for a story. Like Doctor Who, there are just an amazingly plenty number of facets one can dig to tell a good tale.
Pehaps it can focus on the Aurors or people in Azkaban? Ah, I'm getting already getting excited.
