While most people go for large wildlife, I like to find the little ones like this cricket frog on the Katy Trail
Or this freshly hatched horned lizard on the north rim of the Grand Canyon.
Or this wandering tarantula in the canyonlands south of La Junta, CO
I've also see the western collared lizard (don't have a picture but
it's like this one) around Grand Junction. Truly bizarre animals given that they are blue and might as well have a neon "Eat Me!" sign when they are standing on red sandstone.
I have also seen a
ground snake (Sonora semiannulata) in southern Colorado. These are truly strange animals as they are bright orange with black spots. I thought the one I saw was a toy until I touched it and it moved. I reacted like I would with a rattlesnake...i.e. I jumped into the air and didn't come down until I knew where the damn thing was going