Considering The Professor Who crossover doesn't look like it'll go far, I've come up with some other Crossover ideas,

My Little Dead Space: Odyssey (OCs Only)
Mass Effect: Omni-Pony (OCs and One Cannon Character)
Halo Ponies: Bloodgulch (OCs, Based of Red Vs. Blue)
Universal Ponies: (OCs, Humans *Work In Progress*)