Hidden within the instruction manual for the upcoming LEGO Dimensions Level Pack: Back To The Future (71201) are images of other LEGO Dimensions packs. This includes unannounced themes like Doctor Who, Jurassic World, Portal, Scooby-Doo and The Simpsons.
This means there will be additional levels based on Doctor Who, Portal and The Simpsons. It looks like we will only getting the Jurassic World & Scooby-Doo characters though. You can see all the Level Packs, Team Packs and Fun Packs that will be available below. Thanks to Brickset for discovering the new themes.