I’m not going to deny I only know of 2 other Sirius entities. One is the constellation, better known as Canis Major (which is also a black canine, so the only connection to my Sagittarius is being a constellation), and the other is an antagonist in the Bomberman franchise:
(I just liked this picture, I know it isn’t the original model)
Also, best of luck with growing your own pet! They’re extremely useful, even if they are a blight to the game structure.