Creative right? So get to it.
My top 3 are definitely shapeshifting, flight and invisibility. Shapeshifting is mainly for comedic purposes to be honest I don't feel like I'd really abuse it to get power knowing myself other than to fuck with people and get out of tight situations. Like being able to be George Bush whenever I want sounds pretty cool you know.
Invisibility is also just to fuck with people and get out of rough situations.
It's either flight or speed but I think flight is better because you can fly really fast and then there's a lot less obstacles and of course the thrill of flight so it's generally a win-win.