It’s always struck me as a little odd that the key to the TARDIS wasn’t more intricate. On one hand, a plain key suits the Doctor, but on the other hand, I’d love to collect some artful keys. It turns out a few of the previous Doctors had fancier versions, and you can see them in Terrasolo’s key collection.
She made the piece to celebrate Doctor Who’s 50th anniversary, and she used screen caps and production photos for reference. Where she couldn’t find quality images, she made an educated guess. For example, she’s not sure if the Sixth Doctor’s key was ever seen on screen.
You can see a larger image and read more about her process for creating the replicas over at DeviantArt.