I've made these as a sort of test if it's possible to make head sides for coins from photographs, which are used as height fields.

The animal image sources are public domain:

http://www.pd4pic.com/-bobcat-lynx-wildcat-animal-mammal-closeup-head.html
http://www.pd4pic.com/wolf-canis-lupus-animal.html
http://www.pd4pic.com/carrion-crow-corvus-corone-crow-raven-bird-songbir...

The yawning cat (actually a lynx) turned out pretty nice, the wolf and the raven didn't work so well, even that I tried several methods of turning the photos into height maps.

I have no idea if these will be useful in a game project. I've tried to offer a variety of views, in the hope that the one or other might be useful.