8. Delenn Babylon 5
It seems as if the Doctor always has a human companion and theyre generally from the present day. For one episode, The Snowmen, the writers toyed with the idea of the Doctor travelling with a Silurian, a human and a Sontaran not that much travelling was really being done. And they were pretty much dropped, or so it seems, when he found a human to travel with. Obviously, its more relatable for the audience to have a human on-board but for once it would be nice to have an alien by his side. Its for this reason that I think Delenn would be a perfect companion for the Doctor. Shes an alien from the future but thats not all she has to offer. She started off quite shy but grew to become decisive, articulate and strong willed: qualities that are useful for a companion to have. Despite being a military leader, she would get along well with the Doctor as both despise violence and will only fight when necessary. Another perk of the Doctor taking Delenn along for trips in the TARDIS, is that, like him, she has a much longer life expectancy than humans. This means that the pair could travel together for years, without the Doctor having to cope with losing yet another friend.