Going into sewage vats and breaking up solidified waste and oil clogs

Deep sea oil rig repair

Underwater dam repair

Driving public transportation (not enough to maintain a system)

Elder care (there is a worldwide lack of people willing to clean up piss and shit of often angry, sometimes aggressive people and deal with regular loss for bad pay, much less in an ideal profession freedom world, relative to the amount of people needing care)

Forensic pathology is something that very very few people enjoy also, but is very needed.

Urine farmer (hunting luring, sprays for animal repellant)

Coal miner

Any precious or rare metal or stone miner

People love intellectual jobs, creative jobs, and some public service jobs. It is much much harder to find people to do body-destroying terrible-condition manual labor jobs. Ideally those are the jobs to be replaces, but of course capitalists want to replace the former category of jobs because those cut into their profits more.