Okay, here goes...
Lena Horne, Joel Grey, Harvey Korman, Avery Schrieber, Phyllis Diller, Rita Moreno, Connie Stevens, Florence Henderson, Sandy Duncan, Jim Nabors, Paul Williams, Ruth Buzzi, Steve Martin, Bob Hope, Zero Mostel, Julie Andrews, Bernadette Peters, John Cleese, Dom Deluise, Edgar Bergen (and Charlie McCarthy), George Burns, Rich Little, Milton Berle, Don Knotts, Pearl Bailey, Leslie Uggams, Roy Rogers and Dale Evans, Lesley Ann Warren, Helen Reddy, Mark Hamill, Dudley Moore, Jonathan Winters, Carol Channing, Dyan Cannon, Wally Boag, Loretta Swit, Marty Feldman, Buddy Rich, Tony Randall, Senor Wences, Brooke Shields and Carol Burnett.
There may have been a few others, but if I wasn't sure, I left them off.
Whew! Now, if I were to list
where I saw them, it would take another three pages!
P.S. I will say that I saw Edgar Bergen and Charlie on the set of "The Muppet Movie".