So we know Lightbulb's primary ability is are her electrokinesis, Paintbrush their pyrokinesis, Balloon his flight, Goo his malleability, and Candle her Inner-Flame, but I think I know how to expand on these.

Lightbulb - I think I can see her being able to project lightning bolts from her hands and basically electrocute someone by becoming a lightning rod or manipulating thunderstorms and controlling when and where the lightning shows up. And she'd totally forgo "With great power, comes great responsibility", knowing her.

Paintbrush - I think I can see them using their pyrokinesis as basically firebending in combat if you've ever watched Avatar. They can levitate/fly using fire from their palms like The Chosen One from AvA, their bristles being a brilliant flame, and then even able to shoot fireballs or even breathe fire if caught in a pinch. And unlike Lightbulb, they know that with great power, comes great responsibility.

Balloon - I see him able to fly on command, like just pushing up off the ground and able to levitate/fly but he can control it, but there has to be helium softly rocketing out of his opening if he's levitating, but when he's flying the helium comes out like a rocket.

Goo - His malleability allows him to become anything, so I see him doing something like being Plastic Man from DC. 

Candle - We know with her Inner-Flame she's pretty powerful and she can levitate people with it as well as use telepathy, so there's really no expansion on it. 

I just realized how we can upgrade the powers of some Inanimate Insanity contestants.