I've had at least a dozen different pets in my time playing:
-Baby Bounce
-Boopis
-Frawn (still selling)
-Fritterz
-Marshruto
-Narito (still selling)
-Pablet
-Quackman (still selling)
-Stalker Jr
-Stalkling
-Tebrumpt (I don't remember if I had one or not)
-Technotron
-Topper
But I've never named any of them since I've bought every single one via trade.