CAPCOM

Megaman-
Zero- Xx-IBeRiku-xX
Ryu-
Ken-
Chun Li-
E. Honda-
Blanka-
BlackHeart-

Marvel

Wolverine-
Storm-
Cyclops-
Jean Grey-
Nightcrawler-
Spiderman-
The Hulk-
Deadpool-

D.C. Comics

Batman-
Wonderwoman-
The Joker-
Superman-
The Flash-
Cat Woman-
Batgirl-
Super Woman-

If you added the total the amount of characters in all is 24.
You can be one person from each world but that's it. Beware if you have more than one canon you may have to let some spots go as more people join and request.