Waste pickers in the clothing canyons of Ghana, or any other landfill/wasteland
Volunteer caregivers for people with disabilities, especially in places where there are limited or no social safety nets
Street vendors like the children hawking goods in Yemen or Samoa or Zimbabwe...
Cleaners, such as the Sewer divers in places like India where there is no protective equipment provided
Food services workers.
"Domestic" services workers like childcare, housekeeping, etc. I include victims of forced marriages here.
All other exploited, outsourced, trafficked, and/or forced labour, such as the cobalt miners in Congo, or the clothing sweatshop workers in Bangladesh, or the Phillipines call centre workers, or the hazelnut pickers in Turkey, or construction labourers in Qatar, or the chaingangs in the US.
Kitchen staff, for the most part, work long hours in chronically understaffed kitchens for very little pay. You get a break when things slow down and chances are you're going to be eating, hitting the bathroom, and trying to get a little sit time in a milk crate out back in that short little window (hint, pick two of those, the third might not happen).
You get burned, cut, over heated, covered in filth, and breathe in noxious crap all day from stoves, fryers, industrial cleaning chemicals, and other things.
You, probably, and a lot of your coworkers are short tempered, sore, tired, and possibly on drugs or alcohol. You are surrounded by ideal weapons for hurting others and you will be in or see a fight every so often.
Wait staff pretend to like you but really they work shorter shifts, go home relatively unscathed, and make a fortune in tips. So you also dislike and resent them. You don't want to but see above.
You work when everyone else is off so you end up hanging out with people in similar situations who aren't always the best people for things like networking into a better job. They really like partying though, and who needs a future.
Then you get a little older. Maybe you are running a kitchen and finally don't need to have roommates to afford the horrible apartment but you're only there about seven hours in a row at any given time. You met someone through friends but they don't see a future because you are always working.
Eventually, health issues force you to find other work and you claw your way to normalcy 15 years behind everyone else in retirement saving, salary growth, and so on.
Speaking as a surgical tech: hospital janitorial staff, and sterile processing staff. They are INVISIBLE until something goes wrong, then everyone likes to bitch and point fingers, but they bust their asses constantly to keep us from becoming a giant pathogen cocktail. Hospitals would be fucking disgusting in the scope of like, idk, 2 hours, without those peeps.
Been a little bit since I put one of them in for an award. I think it's time to flex my keyboard again.
Certified Nursing Assistants (CNAs). These people do the grunt work at nursing homes. They change bed pans and wipe butts, they fetch things, help people stand and sit, and generally get talked down to by the lower level nurses. When I did ambulance transfer, they were the ones that actually knew the patient’s normal mental state, and how they’d been changing over time. All for minimum wage.
dirty diapers that someone couldn't walk 7 feet through the Walmart parking lot to throw in an actual trash can
empty boxes for: flat-screen TVs, Car seats, memory foam mattresses, or Amazon purchases
disposable vapes
trash bags that someone decided needed to be left in a parking lot instead of in a dumpster
So. Many. Plastic. Hangers.
receipts
grocery bags
candy wrappers
Edit shattered glass, but it makes that gravel in a vacuum sound when the truck sucks it up, so that's nice.
And the only time I get thanked is when my employer asks me to do extra work because there was a storm, another driver was out sick, another driver needed help on a site, or there was a big event that needed to be cleaned for/after.
Step parent. While not entirely thankless (depending on the kids involved) it's tremendously underappreciated.
So much expectation that you do things for kids that aren't yours.
Don't get me wrong - it can still be rewarding in many ways, and my stepkids and I love each other like blood. We have a fantastic relationship.
But it gets under my skin every time I think about how little their own father has done for them, and I've had to pick up the (financial) burden, yet that prick will be the one who gets to walk my stepdaughter down the aisle.
Health care aide. They get paid a pittance to clean up people who have pooped themselves. They should get 300 dollars an hour and a bottle of tequila per shift.
They are usually not responsible for the bad decisions but are responsible for taking the heat for them. They are also powerless to actually influence most decision making.
But people will just flame them for being "bad at their jobs" or something like that.
Detectives who work on CSAM cases. They have to watch, document, and describe the offending material in order to enter it as evidence. Then they get undeserved hatred for working with law enforcement.
There are several jobs that are frequently mentioned in discussions like this that are actually thanked all of them time.
Nurses, teachers, fire, EMTs and police are always mentioned. They are hard jobs and mostly under paid. However they are constantly thanked, businesses give discounts and commercials and politicians thank them endlessly.
Grocery store workers, butchers, plumbers, electricians, custodians, truck drivers and most "menial jobs" are completely thankless. Think of the last time you saw a 10% off for nurses and if you've ever seen 10% off for overnight stockers.
My wife is a school based therapist. The parents routinely cancel without notice. The kids have behavioral problems and trauma that makes interacting difficult and stressful. Not to mention that she has to read through the kid’s trauma history that requires them seeing her in the first place. Not a lot of thank yous for that kind of work.
Software engineers/developers. They come up with software that everyone uses daily. But they work in shitty conditions, get kinda low pay, and because they're not as visible as writers and actors, are not able to hold a strike for kickbacks when their software is used or is still in use.
They basically built the modern world, but are exploited so that the ones who own the company get rich off their backs.
User experience designers. We are too often the lone voice for the user in teams of very smart people who think that being smart is the same as being right, working for business-minded people who are measured by production rather than quality.
We are the oracles for feature failure, and we are rarely listened to. We try to do the best we can, while refused opportunities to research, and are often brought in last minute to improve things that have already caused expensive usability and maintenance nightmares, and are blamed for being "expensive" and "out of scope" when we try to mitigate the damage.
And if an app sucks, we are the first to be blamed. But if you are a genius at your job, no one notices that you did it.