7. Zoe Heriot, 2nd Doctor's Companion
Zoe Heriot is a little cutie pie with the such a smart brain. She's a human calculator and just flat out awesome for all the things she could do. She has an IQ close to The Doctor's and she also has a photographic memory. Along with Jamie, she was a great companion. Unfortunately she got her memory wiped. When you see how she was and how she acted alongside The Doctor, she seems like someone who'd be fun to have as a friend. Also, her genius mind and knowledge of mathematics, could help out anyone in school. She was adorable as well.