7. Erik Selvig
Erik Selvig, he's a character that was created specifically for the Marvel Cinematic Universe. He has appeared in both Thor, and The Avengers and will be making his return with November's release of Thor: The Dark World. I know his inclusion is a bit of a stretch, but his character has played such a crucial role thus far in the franchise that it is impossible not to bring his name up here. Agents of S.H.I.E.L.D. is about a group of Agents that travel around the world and discover scientific phenomena, so is it that far out of the realm of possibility to believe that there is a place during the course of these super-powered hijinks for Selvig? Yeah, Stellan Skarsgard is kind of a big name and hasn't made a habit out of appearing on TV like some of the other names on this list, But he was on Entourage, so it has happened before. I'd think it might also be much easier if he's already around doing principal photography on Thor, and he's asked to show up on AoS for a few scenes. His is one of the many great characters, and I really don't think we should count out the possibility of a cameo.