All types of animal skulls and bones. Some I’ve bought(non-native or from other collectors, always look for ethical sellers), some I’ve found in nature, and some I’ve collected from processing found remains.

I mostly just clean up those that need it and display them(though I’ve been toying with branching out into painting some though every time I get a new one in a species I already have I find something unique or endearing to me about it and don’t want to change it, lol.) Sometimes I use them for art reference or in photography. I have a few I just like pondering over, ex. they have injuries that showed up in their bones and I’ll study them and speculate about what caused it. Those are my favorites, though I always hope they didn’t suffer, as they’re a bit unique. Granted, all skulls/bones are one-of-a-kind if you think about it.