Gurps Bestiary : A Compendium of Creatures for Roleplaying Campaigns by Steffan O'Sullivan is basically what you would expect it to be. A variety of animals, monsters and other beasties of all shapes and sizes.
They range from mundane to monstrous to magical, so it should give you some ideas, or be handy if you need some quick info.
3 out of 5
The above link is the complete list of post from this blog, updated each week, if you want to browse like that rather than search.
This list is quite long, and has become longer than I ever thought so in the interests of loading speed it is now situated elsewhere.
Similarly I am working on a simple website to browse by author that combines Free SF Reader and Not Free SF Reader that is extremely bare bones now, and can be found at the second URL above.