After seeing this thread, I had to go through my research and come up with some answers. Assuming that we're counting the daytime and nighttime versions of the '60s \"Password\" as one version and all of the ABC variations as one version, then here is the list of celebs who have played all four versions. You may be surprised.
Betty White
Bill Cullen
Nipsey Russell
Anita Gillette
Robert Reed
Pat Harrington
Lucille Ball
Noticeable absences from the list: Dick Gautier, Greg Morris, Dick Martin, Anne Meara, and Patty Duke, all of whom never played in the '60s; Jack Jones, Tom Poston, and Phyllis Diller, who never played the ABC version; Abby Dalton, who never played \"Password Plus;\" and Orson Bean, who never played on ABC or on \"Plus.\"
Brendan