Sounds like a neat game. x3 I'll give you some suggestions if you'd like, too.
Fantasy creatures POSSIBLY (unless you want the game realistic with dragons in it), such as unicorns, alicorns, pegasus, griffins, hybrids, bears, and certain selections and markings for sand cats, fishing cat's, and dholes maybe?
It's a lot, yeah, only suggestions for updates and stuff though if you continue it's progress well. If I could and wasn't so lazy and would get on my butt and learn, I would try and help. But I literally suck... xP at markings and mesh making, plus I only make .blend files if it's a mesh, haha.
Also, an active and/or extinct volcano, arctic/ice age ocean, rain forest and/or jungle are cool if you need suggestions on lands and stuff. I wish you good luck on the game! :{o and if I had the time I might be able to help you with some stuff, I guess. merr...