I set myself a challenge. Go overnight/multiday hiking using only gear that I had found.
I wanted to stick as close to possible to my normal hiking packing list.
I don't think so
The following are items I've not found... yet...
Tent/shelter
I've found a few broken tents, and I guess I could have fashioned a shelter from them. I had a mate find a great quality tarp 5 metres from where we parked once. Just missed out!
Sleeping bag
While I've found bed rolls, blankets eaten by moths and rodents, and even a whole swag and mattress (almost new!), I'm yet to find a sleeping bag or other sufficiently warm sleep layer.
Clothing
Over the years I've found heaps of clothing, but there's a limit to what I'll wear (even after it's been washed). While I've found raincoats, fleeces, beanies, socks, underpants, thermals, gloves (never a pair), shorts, hats, shirts, and sunglasses, I am yet to find:
insulated jacket
shoes that fit me (found plenty that don't)
pants
watch.
Stove/burner.
Trowel
Compass
PLB (Emergency Beacon) Understandably!
First aid kit
But pretty much everything else I've found at some time or another.