Companions are a permanent fixture in Doctor Who. They are the Doctor's closest friends who join him on his journeys through space and time, aiding him in his quests to defeat evil and make the universe a better place. Generally, they are ordinary members of the public who he inadvertently befriends and ends up asking them to accompany him in the TARDIS. Wouldn't it be interesting if the Doctor could pull characters from other sources of fiction to join him on his adventures? There are a plethora of interesting existing characters who would make fantastic companions for him. One particular source strikes me as having a huge abundance of characters who would be great travel companions for the Doctor - cartoons. Of course, it's illogical to have an animated character join a live action television show, but we can imagine, right? With that in mind, here are ten animation characters who would make great companions for the Doctor.