The McDonell Douglas MD-80 aka "Super 80" is still in use at AA, but is due to retire within a few years. Dunno if anyone else will keep flying them longer.

If you can still find a Fokker big regional jet (so big you might think you're simply on a smaller mainline plane), those are slowly disappearing, since the original company went poof some years ago. (Though a new company is trying to restart them.) I flew one about a decade ago when KLM CitiHopper flew them on short hops from AMS. I think it was probably the Fokker 70, since KLM CityHopper still apparently flies those.