One place to look would be anthology shows like Twilight Zone, Outer Limits and Alfred Hitchcock's two shows, because each episode has a different set of actors.

Good point Grant, but since most of the casts for Twilight Zone were small, I'd be very surprised if any single episode had a lot of actors who subsequently appeared on Columbo, but I could be wrong.

Actually, after I posted, it occurred to me that the Bob Newhart Show had four actors who played regular or recurring roles (Suzanne Pleshette, Marcia Wallace, Jack Riley and John Fiedler) who appeared on Columbo. I found at least one episode with three of those four plus two more(Chuck McCann from "Double Exposure" and Joyce Van Patton), so that ties the record of five, so far.

Not sure about the occurrence of five, though it was cute to see Roddy McDowall and Anne Francis from "Short Fuse" reunite in an episode of "Matlock" years later.

Another show with a lot of Columbo actors was "Burke's Law".

It starred Gene Barry and Gary Conway, with regular appearances by Michael Fox, so that's a good start right there.

Found one episode ("Who Killed Annie Foran?") that had Barry, Conway, John Cassavetes, Gena Rowlands, and Don Ameche.

Hi.

Yesterday I watched the TV movie "Fireball Forward" (1972), with at least eight names related to "Columbo": Ben Gazzara (director in the series), Ricardo Montalban, Anne Francis, Dana Elcar, L.Q. Jones, Eddie Albert, Kenneth Tobey and Don Eitner.

Regards