Don't take yourself too seriously.
I want the power to bonk really hard
I don't have that information really at hand at the moment this was more to check if people were even interested to start with. I still got to figure out all the details of the CS I want to do. But sure I can send a message if you really want.
Its probably going to be case by case. As far as I guess 'races' go (I mean its more so different groups really and their abilities) the only real thing I'd say is limited is I'd be sticking to canon stuff so stuff like Hellverse or the bounts probably won't be a thing, though I'm always open to being asked about something or pitched it. Just expect me to probably be iffy about adding some new thing in.
Power wise creativity is always great. I am a stickler for balance so if you got something powerful I would expect something that counters or limits it to balance it out. Heck even if you have a very mundane power I'd still expect some sort of drawback even if its likely some matching mundane drawback. The world might be out of balance but your characters best be at least to some extent balanced.