I've read of many over the years.
There's a guy whose job at the factory where they manufacture bathroom scales is to weigh himself on every scale that comes off the line, making sure the weight on the scale matches that on an accurate doctor-type scale.
There are drivers who work "honey trucks" which empty tanks of bathrooms not connected to sewage systems. (I worked in a place with such a bathroom. No, it did not smell.) The two honey truck drivers I knew both had suffered injuries leaving them entirely unable to smell anything, which seemed like a prerequisite for the job.
Assembly lines often have people whose tasks are so limited they literally tighten the same two bolts or paint the eyes on identical plastic dolls all day every day. Luckily, manufacturers long ago saw the wisdom in such employees swapping jobs often.
Have you checked out Mike Rowe's "Dirty Jobs" on youtube or elsewhere? His were all yucky, and some of them seemed pretty strange as well.
Maryn, who knew a girl whose father was a chicken sexer--and made a lot of money at it