I have nothing to add regarding other peoples' characters but I wanted to mention that I read the whole thread thus far and loved seeing everyones' posts. :D
I mostly do one-on-one roleplays, with one person acting as a game master. That often leaves my characters with whatever skills nad power levels they gain during their respective roleplays and oftentimes they end up really OP. Which I like. I mean there are no other players, so I don't have to worry about overshadowing everyone and if everyone is having fun then what's the harm? I think there's a certain wish-fulfillment element in having a "cool" character and it doesn't really rob the story of any conflict, just displaces it, putting stress less on how a character is going to accomplish a particular goal and more on how they and their loved ones are dealing with their powers.
I think my most OP character must've been contemporary!Nimue Jakande. She started out as just a blind teenager from a fictional north-african village but during her roleplay, thanks to a very generous GM, the girl basically became a god.
She was half-messenger - a "messenger" in that setting being basically a piece of Sheme, the goddess of life and light. Her powers included shapeshifting and (to quote my game master) "basically anything you can imagine regarding manipulating light or healing and stuff. If it's well-explained I'll probably allow it".
So stuff she did involved among other things other things: turning herself to different animals (one form per species), being able to use Sight ("feeling" the shape of everything the light touches around you without the use of eyes), being able to cast illusions, heal injuries (including re-growing limbs), create flashes of light and heat, manipulating her own senses through partial shapeshifting (giving herself the hearing of an owl or shutting off her sense of smell for example), warming up herself or others, flying (with wings of light or some other assisting prop like that) and tapping into the mind of another person to see what they saw (used recreationally between her and her boyfriend so she could experience what colors look like), barriers and projectiles made of light etc.
The main limit was that the source of power for messengers came from the sun, so they were essentially working on limited batteries whilst indoors or at nighttime. It wasn't a big deal until the main villain up and killed the goddess of the sun, plunged the world into darkness and then made everyone believe my character had done it on national television. Fun.
She used her power to heal some people quite publicly and gained an online following for that. Mostly she'd use her powers to goof around harmlessly, however. She'd also give in to temptation and misuse the powers from time to time, once emptying a convenience stores' cash register and using the money to essentially buy treats and a smartphone. Most of the conflict came from her immaturity in handling the sheer volume of what was granted to her, as well as fighting against equally OP characters to save humankind.