Literally everything and anything. You think it, I have it. Werewolves? Yep. Vampires? Yep. Demons? Yep. Zombies, fairies, pixies, angels? Yep, yep, yep, and yep!
I have so many different, made-up races/species within my story, and they are applied to all different animals, giving them different properties. For example, the first animal we get is the Yehenma Hog. It is obviously a species of hog/pig, but there are a few differences varying with their fur, tusks, and living availability. The hog lives in the Yenhema swamp, and it is accustomed to strong foe, thus, it has built up a venom in its tusks that is rather potent to lots of stronger foe.
Edit: I completely skimmed over the main fantasy creatures that my MAIN CHARACTER IS TURNED INTO! A strigoi! Gosh, my mind is jumbled. Now I know lots of folks don't know what a strigoi is, well, they are a Romanian monster that is a mixture of a vampire and werewolf. I find them, in my story, similar to a ghoul. These creatures are incredibly rare, and they are simply that of being heard through fairytales. The few characteristics about the MC as she isn't completely transformed is that: a.) when angry or hungry their eyes turn bright red, such as that of a dragons. b.) their fangs elongate outwards to be about an inch in length. c.) black veins travel up their limbs, these limbs soon start to turn black the longer they are in blood lust. It is noticeable in the arms and legs. d.) their nails elongate to be able six inches in length per nail. They are sharp, deadly, and 10/10 wouldn't want to piss off.
However, the full form is even scarier. It is closer to that of a dragon & vampire monster, where their size varies from eight feet to ten feet. They have glorious velvet wings that they used to fly. Their skin is darkened and, some even describe it as, a bit scaly. Their muzzles are large, teeth sharp, and their eyesight is so on-point that they can catch the slightest movement of a spec of dust.