Nintendo:
Main: Luigi, Daisy, Bowser, Rosalina, Samus Aran, Wario, Waluigi (I'll add more if I think of some more)
Friends:Yoshi, Toadsworth (I'll add more if I think of some more)
Enemies: Shy Guy, Bob-omb, Chain Chomp, Metroids
Sega:
Main:Silver, Blaze, Marine, Knuckles, Julie-Su, Espio and the rest of the Chaotix, Sonic and Tails
Friends: Shadow, Rouge, E123-Omega, Amy Rose, Cream the Rabbit, Big the Cat, Tikal and Chaos, Manic and Sonia, Mephiles, Gmel, Babylon Rogues
Enemies: Dr. Nega, Mecha Sonic/Metal Sonic, Bean the Bird, Metal Team,
Capcom:
Main: Chris Redfield, Rebecca Chambers, Claire Redfield, Jill Valentine,
Friends: Barry Burton,H.U.N.K,
Enemies: Albert Wesker, Zombies, Hunters,