These are all great choices, but I'm gonna go unconventional and say one of the myriad of actors/actresses you saw on every damn TV show, and many movies, of the late 50's, 60's, 70/s, that you didn't know the name of, but you sure knew their faces. They would be in Dramas like Twilight Zone, Star Trek, Mannix, Comedies like Dick Van Dyke Show, Batman, Gilligans Island, an occasional move. I love the game of seeing someone, and saying wasn't that person in xxxxx and yyyyyy. To put in a name, I'll go with Jack Klugman. Was everywhere, did everything.