Too many to even list.
Yeah, hindsight is 20/20, but it would have been nice if, even now, more foresight was used, like with the B-26 "Flak Bait." Think of all the true "time capsules" there could have been. You always read about "saved" aircraft that were later scraped, because of storage space. I'm sure places like Davis-Monthan could have easily handled tucking away a lot of crated aircraft at an out of the way area without infringing on base activities in the least.
Even without any preservation measures, simply disassembled, crated aircraft, stored for decades, would be far better then "wreck recovery." I'm not saying these wrecks shouldn't be recovered, nor am I trying to take anything away from those dedicated individuals that rebuild them. I'd just find a 100% original aircraft in it's just uncrated from storage state far more historically interesting then a 5% mix and match of original parts attached to 95% new build parts, pristene replica at an air show. As meticulous as a rebuild/restoration may be, its individual historical significance is lost.
Just my 2¢ worth.