Skulls and bones galore!
Phenome10k.org hosts a massive archive of digital models of animal skulls. Created by Dr. Anjali Goswami of the London Natural History Museum, the site features hundreds of CAT, MRI, and surface scans of various animal skulls and bones. The models can be viewed in your browser or you can create an account and download the .STL. The files are sortable by taxonomy, geologic age, elements or ontogenetic age. The site is a wonderful resource whether you’re a student studying animal anatomy or an artist looking for inspiration for fantasy creatures or creepy monsters! (But please note - all models are licensed under the International Creative Commons NonCommercial 4.0 International License.)
If you have a moment after checking out Phenome10k.org, take a look at some of the other research done by Dr. Anjali Goswami on her research site!