Here's the first of a few Simpsons Dissidia Character sheets. This one being Lisa.
Each character has five outfits, one outfit is their standard design, which is Lisa's orange dress, and an alternative outfit, which I haven't thought of yet for Lisa.
They also have an Ex-Mode, which is a transformation into a more powerful form, in Lisa's case, she dons her Lisa the Conjurer outfit, and should be related to the outfit the Ex-Mode form is for. So there would need to be some variation to Lisa's alternative outfit for her alternative Ex-Mode.
And they have a crystalline version of themselves to act as "random" enemies, they aren't named after their character, but rather two words that identify the character portrayed. Hence "Soulful Vision" for Lisa.
As a challenge for the artists out there, why not try this idea out on your own fan characters?