It's getting down to where there's very little that I need. Most of this list is just stuff I could use if you have it lying around and you're coming to visit.
Metal Roofing
Rusty corrugated iron would be perfect! Also good, and much less likely, would be uncoated stainless steel, anodized aluminum, or Galvalume.
Coarse Gravel
For wall foundations.
Straw Bales
Ideally winter wheat. This is for cob, and also for a composting urinal.
55 Gallon Metal Barrels
With lids, I can use them for storage, and without, I can use them for rocket heating stoves.
15-17 Gallon Metal Barrels
Ideally, with a lid that lets a little air in, as the intake for a rocket heating stove.
Water Heater Tank
Also for rocket stoves, good for the wall that goes inside the big barrel.
Stovepipe
Eight, six, or five inch.
Unglazed Clay Pots, whole or broken
I can use the broken ones for Terra Preta, and the whole ones can make evaporating refrigerators. It's even better if they don't have holes in the bottom.
Plastic Five Gallon Buckets
Best if they've held food and not toxic stuff. No lids necessary.
One Gallon Glass Bottles
Can't have too many.
Sawdust
For composting toilets, trails, insulation. Can't have too much! Partly composted is fine, but I don't want any from treated lumber.
Tarps
At least 6x8, for covering stuff and mixing cob.
Double-paned windows
Either small ones that open, or big sliding glass doors which I can use as tall windows.
Milk Crates
As many uses in the woods as in the city.
Metal Bathtub
I eventually want to build a bathhouse with a tub heated by a fire. I've heard different things about whether a cast iron or a steel tub would be better, but I think I can work with either one.
Vermiculite / Perlite / Pumice
Insulation for rocket stove, or if I get enough, for the cabin walls, or for garden soil.
Rocks
In the 10-100 pound range. The land is not that rocky and they have many uses.