On May 31 a U.S. Navy F-5E Tiger II third generation fighter crashed into the sea off Key West, Florida, with the pilot ejecting safely and being recovered by an MH-60S
F-5s remain USN - USMC adversaries (USAF has aggressors) because they're paid for, fairly cheap to maintain, and upgradeable. Besides that, they're just a whole lotta fun to fly.
One of my USN friends established Top Gun (damn autocorrect won't allow the proper one-word variety.). He still says: give him 100 F-5s with pilots flying 30-40 hrs/month, a radar missile and ECM support, and he could own a desired block of airspace.
I am not sure how many nations still fly the F-5. Jordan still has a bunch, including some they got from Europe second hand. S Korea had them too; a friend of mine once entertained himself by out-turning them with his B-52. I wonder how many of them are using Fuzzbusters, like that Red Flag pilot.
I guess Canada no longer has them, and there is a rather negative video about the CF-5 on Youtube. I'd guess that Mexico probably still has them.
Iran claimed to be building new ones, but that may have been simply overhauling and upgrading their old ones. In fact one guy I know showed a picture of what supposedly was one of the new Iranian F-5's but in reality it clearly was a photo of a USAF Skoshi Tiger F-5A in Vietnam, complete with an F-100 parked in a revetment behind it.