Sure, sure—the TARDIS is always evolving along with the ever-regenerating Doctor, but what of the TARDIS key? One clever artist plotted out the evolution of the TARDIS key from Doctor Who. And it is delightful.
Created by Terrasolo Pictures, this is really just a wonderful collection of TARDIS keys. And I would probably wear the 7th or the 8th Doctors' key as a necklace.
The artist also included a breakdown of their collection:
I made this piece for the 50th Anniversary of Doctor Who using my own TARDIS key collection. It started a a project to archive my key collection and then grew into a celebratory piece.
The Classic Series Yale keys are as close to the show as I could get them. Using screen caps and production photos many of us on the Replica Prop Forum were able to match many of the keys used on screen. However, due to lack of production photos and low quality film footage for some of the keys it's hard to get 100% accurate details on. The First and Sixth Doctor being two of the hardest (the Sixth may not have been seen on screen. I am still double checking). So due to this some of the Yale Keys are close enough or idealized versions of the classic keys.
The Classic Series special shape keys (Third, Fourth and Seventh) are accurate replicas - made by Mooncrest Models -to match the screen used props perfectly.
The TV Movie key is not a replica, it is the same 800-Trekker key that was used in the show. That is I bought mine from the same place as the TVM did, not that my key is the screen used one. But they are identical.
The New Series ERA keys are 100% accurate to the screen used keys (minus the teeth cutting as they fit the lock to my TARDIS instead).
The New Series keys that have been sanded of the logo (Keys like The Tenth Doctor, Sally Sparrow, Perception filter, etc) are very very close replicas (pretty much one detail off). The brand of key we used on the RPF to replicate the one in the show is called JMA. The actual brand used in the show for the sanded keys was Silca. We have not yet found blanks of this key to use. Though I am rather happy with the JMA keys.
The Eleventh Doctor and Clara key is a sanded Yale key. Very similar to some of the classic, just sanded to remove the logo like the JMA/Silca keys were.