5. Harley
This little kid was probably the best thing about Iron Man 3. He served as a means for Robert Downey Jr. to practice his comedic timing, and actor Ty Simpkins proved that he could keep up with him. Since Iron Man 3, Simpkins has signed a three picture deal. Details of his role, or in what titles he will be appearing are completely unknown at this time, although At the end of the last movie, Tony sank some of his dollars into upgrading the amateur inventor's backyard lab into something a little more Stark. The show's first episode dealt with Extremis, so if it should come back in a later episode, the team might want to seek out somebody has had experience with it. Wouldn't be cool to see how the team reacts to listening to a kid in a barn? Also, might it also be fun to see Coulson interacting with a kid? Clark Gregg's performance has shown that he's often been seen to be quite a child at heart, so there would be plenty of comedic mileage in sticking the two up on screen.