I think that you've covered it all really; some wrecks remain, known about, in Russia and will stay where they are for now; Scandinavia has a number of well-documented aircraft, some in the water and some in remote places, which could be recovered if resources allow.
Plenty of stuff in the Atlantic, Pacific and Med of course, but usually too far gone to yield anything substantial.
The P-40 was a real surprise to everyone, even a number of self-proclaimed experts who wrote it off as a spoof model uploaded onto the finder's website. Most, if not everything in the desert would be raided by the locals, although the Sahara is one big place, as the P-40 proved. So it's possible, but personally I think that the world's been done now, so unless anyone is going the fetch that B-52 that the Daily Star discovered on the Moon
then we've found it all.