This has made me decide to add a few missing / alt colours of beasts to Petopia (as unused skins). I've had them listed in the forum thread for some time, but now they're up on the main site. They are: the original green and blue direhorns, the original blue Zandalari devilsaur, the original blue axebeak, and the grey crane found in the alt folder.
Hopefully some of these could be restored to the game. I'm a little disappointed the old green and blue direhorns didn't appear in Zandalar. They're quite different, and a lot brighter than the ones they eventually settled on. I also love the alternative blue axebeak, though I suspect in that case it was removed because it looked too much like Toucan Sam.