Used but usable plywood pieces (Grass Valley-Brunswick basin)

I'm rebuilding my lean-to woodshed, need plywood pieces to help stabilize it. Anything 2' x 3' or bigger, and at least 1/2" thick, could be useful. As long as it's structurally sound, I can use it (not worried about nail holes, weathered appearance, paint, etc). Reply with rough measurements of what you've got and I'll get back to you. Thanks!