It's lonely business, being basically immortal and traveling time and space in a body that never ages. Which is why the last remaining Timelord always brings along a friend! Usually a woman, usually from Earth, always somebody kind of amazing. Here, we rank them from mildly interesting to all-out timey-wimey.
We're sticking to the current series (Ninth, Tenth, Eleventh and Twelfth Doctors). Also considered are companions who joined for just one episode of a special.
Photo Credits: The CW; John Paul Filo, CBS; Ron Batzdorff/NBC; George Kraychyk/Hulu; NBC; NBC, Peter Kramer/NBC; Gregg DeGuire/Getty Images; Jason LaVeris, FilmMagic; NBC, Chris Haston / NBC; Chris Haston/NBCU Photo Bank/Getty Images; Vivian Zink/Getty Images; Bill Records/NBC via Getty Images