Oil patch roustabout and roughneck (but I got out of that to keep from turning into a crabby arthritic old man like all the 40 year olds I knew back when I was doing it in my 20's, so last resort at age 45).
Worked in general building construction (concrete, framing, roofing, etc) but same caveat about getting cranky as above.
Used to run backhoes, loaders, and D3- D7 dozers. That was fun and I wouldn't at all mind falling back to it.
As a landlord, I know general home maintenance and repair, and am a pretty good plumber (like working on the intake side lots better than the outflow side
).
I'm pretty good at diagnosing and fixing computer hardware and software problems.
Current job involves Geographic Information Systems, Remote Sensing, aerial surveys, various mapmaking and spatial analysis. Lots of demand right now, and I get job offers all the time, so wouldn't need to fall back on other skills as long as demand is high and I don't burn out.
Also a .gov diver, so it would be pretty easy to credential myself into a "civilian" dive instructor and work as an unbuttoned Hawaiian shirt wearing, wise-cracking, woman hitting-on, beer swilling, worldly, dive guide on some Caribbean island.
If worse came to worse, I know which end of a shovel to hold, but if things got that bad, then I'd REALLY be cranky.....