Hybrid animals is an almost forgotten collection, and has not had any new cards released in it for years with the exception of beefalo. Just releasing one or two cards that buff this archetype could help to dust off this collection and bring it into the meta. There is a lot of potential for cards with the amount of hybrid animals existing on Earth, but that potential is yet untapped by card design.
https://www.livescience.com/animals/strangest-hybrid-animals
Pardon the ads, but this website has a lot of decent info on hybrid animals.