There are 14 Episodes in the Lego Dimensions Starter Pack. I'm uncovering all Minikits and the Rescue of Episode 13: The End is Tri. Getting all Minikits and the rescue will get you 2 yellow Lego Bricks
"The Phantom Zone" Minikits can all be collected by "Wave 1" Minifigures. Minifigures that have been released together with the Starter Pack. Either as Fun Packs or Level Packs.
The Abilities and Minifigures you will need to collect all Minikits and get the Rescue in The End is Tri. I am completing this list here with Minifigures that are not released yet, in case you are tackling this at a later stage. Of course you will only need one of those Minifigures to perform the ability and a Minifigure has more than one ability :