Hoo boy, there's a lot of things:
-Nearly everything in English class aside from grammar, spelling, and vocab. A lot of my English classes have focused on literature, which is useless to pretty much every career and IMO isn't being taught correctly. I've learned more about literature from 3 years of browsing TV Tropes than 12 years of traditional education, and that's pretty sad. Oh, and no one ever taught me writing very well until my freshman year of college.
-Gym. I get that exercise is important, but again, they seem to be teaching the wrong thing. I learned virtually nothing about proper exercise in gym class, instead they're just teaching people how to play sports. And while sports can be fun and all, do we really want to be forcing people to play them when they're not particularly useful in work or everyday life. They're an extracurricular activity, it's great to get involved in them if you're interested but if you're not, there's no real benefit.
-Anything in biology that isn't common sense or health related. Pretty much everything about cells, taxonomy of animals, interesting stuff, but not particularly useful unless you work in health or zoology.
-Moles (from Chemistry class). Not a good sign when you completely forget what they even are.
Contrary to most people, I actually found most of math to be pretty useful (except maybe Calculus). But that's probably more because I work more in tech and office related careers. I suppose if I was in a completely different career field though (maybe something not science or tech related), I'd feel the same though. Science and tech generally requires good math skills. That's pretty much the underlying theme here, a lot of things I've learned are better saved for students specializing in those fields, not for general education.