8. Chela (Snakedance)
I'm always on board with having more male companions -- especially when they're as cool as Chela. He's exactly the type of unique, insightful person the Doctor would want in his corner. While the rest of the people in Snakedance treat the Doctor like a dangerous madman, Chela is open-minded enough to realize almost immediately that he might actually have a point about the Mara. It takes a certain strength of character to throw aside your preconceived notions, especially when your friends and colleagues think you're crazy. Chela is immensely resourceful and unceasingly helpful to the Doctor throughout the entire story. He gets along great with the crew, and it's easy to envision him working well in a number of other episodes. Chela brings a lot to the table -- it's just a shame that Five's TARDIS was already operating at full capacity when they met.