Nitendo VS Sega Vs Sony(note need a Co-GM for this to handle Sony. I dont play much Sony games sorry guys)
THe three biggest video game comnpany rival's characters come together in one universe to battle each other, join alliances and fall in love.
Sonic Shall battle Mario. Kratos the god of war takes on the Hero of time.The eggman shall take on Cortex. The Bane of Hell: Doom guy vs THbe King himself: Duke Nukem. Who will win and which side are you on?

Pokemon in the Mushroom Kingdom?!?
Bowser has a new army of evil trainers and pokemon. Its up to the Mario bros, his friends(Peach, Daisey, Yoshi etc) and Pokemon trainers to defeat him.

Gijinkas
Arceus and his human trainer have decided in order to make pokemon and humans closer they merge them together creating Gijinkas. But the human's personality remains intact. The human who were evil now create a new team. a team named Team Dark(Cliche I know but thats all i got) its up to a group of good gijinkas to take on team dark.

Worlds have collided. The Dark Knight is in Sin City. The First Avenger meets The clown prince of crime. Yokai Academy battles Xavier's school. Shinigamis meets the spirit of vengence. Aliances will be met. Sides will be chosen. Choas will come. It all depends which side you on.

The Chaos Crystals and the Power Stars are stolen by Bower Ganondorf and Dr.Eggman as well as their league of villains. Its up to Mario, Sonic Link and other heroes to stop them

Pokemon Vs Teen Titans/Young Justice
Team Rocket, Plasma and Galactic have joined forced ever sence they arrived in a strange universe of heroes. Pokemon trainers come to stop the teams The heroes believe the pokemon trainers work with the team and after a small confrontation they join forced but the villains join forces with the teams.

Post your ideas or give feed back on some ideas