I found a nice fiberglass 8' stepladder a few months ago. That's been my best find, but my father found a decent aluminum extension ladder years ago, and my wife and sister were traveling together and found a 3/4" drive socket set. It's not like they have any use for it, so it's mine now. I don't know if I'll ever use it, but if I need it it's there.
Found a pretty big toolbox along the highway between San Angelo and Big Spring. Box was tore all to pieces, but tools were scattered for about 100 yards no worse for the wear.
Got more than one Igloo cooler the same way, one with beer scattered along where it had bounced.
Got an 18 wheeler tire one morning about 2am, still on the wheel, when it came bounding down the grade from an I-10 overpass and crashed thru a window into the office I was dispatching from. Scared the benice out of me too.
Good find, I once found a pair of 11r 22.5 semi tires on aluminum bud rims still on the hub on an off ramp. Tried like heck to get them in my truck but had to leave them they where way too heavy and I was in a hurry. Also found a really expensive snowboard with boots still on it, someone must have forgotten to latch them on their roof.