Masta Ace, Dr Dre, Ice Cube, E40, pretty much all of Wu Tang....
Id say its definitely more rare to find those that released their first albums in the 80s (Dre, Cube, Masta Ace) but a lot of emcees that released albums in the early 90s are still going strong.
I saw Ghostface perform last summer. He just turned 50 the other day. The guy still looks like he did during 36 (1992). And can still out rap 99% of the game.