This particular board isn't really separated into different groups or kingdoms of animals, they are all just sort of tossed together. I did this on purpose. What I end up with is a collage of all different sorts of animal images, right next to one another. It really shows you the differences and the similarities between species at random. It can be fun to just scroll through every now and then.
How does this relate to warming up? I've found that when I just doodle, there's a tendency to incorporate some of the same traits into my designs. I'll always go for forward facing eyes and a leathery hide. It's what I like the most and I think all artists have certain "pieces" of subjects they like to draw over and over.
I use Pinterest to give me a fresh set of traits. It not only switches things up aesthetically, it keeps things exciting and challenging. It's almost like slots. Scroll down on your mouse fast and where ever the webpage lands, pick a few animals in that space and smash them together! I've sketched out two creature portraits below. This can easily be done with quick head concepts like these or full body concepts as well. You can see this particular set of animals came up: