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.
What? Developers are definitely not underpaid, I earn more than twice what a social worker gets after taxes.
Invisible is also very dubious, if I tell people I'm a developer, everyone assumes I'm a rich genius who's building cool stuff.
The true heroes of our industry are the admins. If they're doing everything right, nobody notices they exist, but if they do only a single thing wrong or some software has a bug they aren't even responsible for, they'll get the blame first.
In the US developers, especially those that move into management can make a small fortune. Starting salaries are around where many careers peak with a comfortable living salary and the sky is the limit on how much a dev can make