I think that teaching classes would be interesting. I have a lot of industry experience, but I never actually got a degree in the field I work in, and I don’t have any sort of degree that deals with teaching. Is it possible to get a job as a teacher without those?
Edit: I’m in the US specifically looking at teaching college courses, but K-12 could be interesting, too.
I have a degree in CS with a minor in Earth and Environmental Science. I taught middle school science, and could have taught math.