(Matt the Pony’s former companions….well some of them…and Oswin even though she was never really a companion of his…
Namely I drew basically every new Who-companion who has been in more than one adventure with the Doctor. So none of the single-episode-companions. Sarah Jane and K9 got a guest pass for being classic Who companions and Oswin is just there because she’s a companion in canon… even if Matt the pony never got to that part. )
There’s a billion universes out there, I think you’ve gotten ours confused with something else. I can assure you my companions aren’t ponies (thought maybe having hooves would make River stop shooting at my hats).
(Mod PS: to the anon who seems to have decided to try to turn everyone into ponies; IF I’m introducing pony-companions (I mean there’s the pony-doc hiding back there…) I’d like to design them myself, and not use other’s designs or background-ponies. I already have a couple of pony-designs, specifically for River, Rose, Jack Harkness and the Ponds posted on my DA.)
Derpy has made a memorial for our fallen friends inside the TARDIS, in what would have been her room if she hadn’t preferred to sleep under the console every night.