Plenty of fighters have gyms that they manage and coach classes at, like Dan Henderson. That’s pretty straight forward since they’ve been in the gym all their life (usually) and that’s what they know. Plus if they are name fighters like Hendo it attracts more people. So coaching is a job as well.
some fighters get a job as commentators, fight analysts or something like that. Fighting is what they know so they can just call out what they see and what they’re looking at. For example DC, Bisping, Dan Hardy, Cruz, Rashad Evans, Chiesa.. I think even Anthony Smith