Basically: vague animal, give it some design, then a hand on the tail.
the first one looks Aztec. i will definitely make one of those in the future. i have not seen any origami Xolotols anywhere (he is Quetzalcoatls brother, the evil dog god who guards the underworld. http://en.wikipedia.org/wiki/Xolotl ) i designed an origami serpopard from egyptian mythology but accidentally deleted it from my website.https://encrypted-tbn2.google.com
edit] i just thought of a cat sidhe which is a evil black cat who appears at crossroads and tries to lure travelers off the path and will them eat them.
There are a lot of mythological creatures that haven't been done. For instance, I recently designed a monopod recently (one legged humanoid from greek mythology.) I'm trying to design are a hippalectryon as well.
I know there are a lot of Chimera interpretations out there, but God of War's Chimera looks coolest to me. So I designed one based on it. You got lion head under the goat head, and the serpent head at the tip of the tail.