Shed antlers
Every winter and spring, deer naturally drop their antlers, and picking up a naturally shed antler is widely treated as fine on private land with permission - it's not from a hunted animal, so there's no tag or license. TPWD doesn't spell this out in a single rule, though, and collecting antlers (like anything else) is clearly off-limits in state parks, wildlife management areas, and national wildlife refuges. When in doubt, ask. (This is about naturally shed antlers - not antlers from a deer taken illegally.)