Dead things, art things, farm things, nature things.
I’ve got a few! Bird bones are tricky to collect (in the US anyway) because of the Migratory Bird Treaty Act which protects just about all native species and makes it illegal to possess, sell, or trade in any parts of them be it bone, shed feather, nest, or egg shell.
Invasive species like European Starlings and European House Sparrows are fine since they aren’t native and then game birds like turkey are legal too. I’ve got a turkey skeleton I’m working on right now that a neighbor of mine shot last season. Unfortunately I don’t have anything that is for sale at the moment. But as for finished pieces in my collection I have:
An Ostrich Skull
Ringneck Pheasant (aka Common Pheasant) Skull
Guinea Fowl Skull (my fav)
Domestic Cayuga Duck Skull
And this cute little chicken chick. I got it in a box of beetle food I bought a few years ago. I need to make a nice display for it one of these days.