Sketchbook: The Doctor's Backup

Now, I think most Whovians might be a bit busy today, but to celebrate the 50th anniversary of Doctor Who, enjoy this bit of Doctor Who fan art!
I was thinking, which companions would be the best backup for the Doctor if he needed to bring some along?
I stand by my choices.

Left to Right: Jenny, Vastra, Ace, Leela, Captain Jack, Rory Pond

The Prehistoric Lizard Woman, her Wife, the Doctor's Ace-in-the-hole, a Cavewoman from space, the Undying Man, and the Last Centurion. No better choices.

Happy 50th, Doctor Who!