Old bottles, rusted knives, rusty traps (two rusted open in the set position) and lots of critter skulls.
Found the head, antlers and cape of a decent 8 point several years ago, while deer hunting. Something dragged what was left of it into the woods, near one of my stands.
Once found a large horse shoe far back in my woods. Later mentioned it to my uncle, who farmed the land my cabin is on, since WWII was going on. He thought about it a bit, then recalled that one of his draft horses had died over there in the 1940s and he had used the other horse to skid the dead'un out into the woods. The one that croaked was pretty old and had come along with the farm when he'd bought it before the war. He still had horses when I was a little feller, but I can barely remember them being on the farm.
A camp neighbor's woods holds the remains of an old maple syrup shack. Still cast iron parts from the firebox doors and rusted metal pails buried in the debris inside the stone foundation. All the wood is long gone.
Anytime I come across an old foundation, gotta poke around and see what's left.