I’ve gotta agree with Otto. I can think of only a handful of actors that went on to do anything from most of the shows I used to watch. You could make a case that a few went on to careers as TV episode directors (Charles Haid, Tim Reid, Ted Wass) but the majority certainly never appeared in front of the camera with anything approaching regularity. Other than the ones mentioned:
WKRP in Cincinnati
Loni Anderson - a few forgettable roles, some extra spotlight due to relationship with Burt Reynolds
Howard Hessman - some other show as a teacher whose name I forget, then nothing
Gordon Jump - Maytag repairman
Herb, Les, Andy, Bailey, Venus: zilch (unless you count a few reprising their roles on the short-lived “New WKRP”)
(a little more celebrity) Richard Mulligan, Katherine Hellman, Robert Guillaume.
Everyone else - total obscurity. Granted there are more “names” from this one, but the actual cast was enormous. Counting the character names I can still remember, I’m up to 10 on IMDb jsut going down the list.
Hal Linden - a few decent roles in other TV series.
Abe Vigoda - his own spin-off that lasted one season, then some fame, probably due more to being Tessio than anything else. (Beastie Boys lyrics excluded)
Wojo, Harris, Deitrich, Luger, everyone else: zilch.
Nobody of note has done anything. Dave Anderson had some flop as Dave Berry, Markie Post had a small role in There’s Something About Mary, but everyone else - obscurity.
90210, Melrose Place
Luke Perry - some cowboy movie, small role in Fifth Element
Shannon Doherty - Charmed, tabloids
Tori Spelling - tabloids
Everyone else - occasional story mostly focusing on how ridiculous they were then / “where are they now” type stuff.