Omar / Yorick / Harry the Hipster / Pierre the French Rat / Professor Madcliffe / Sam / Limbo Prototype / Moldy Hay (9 episodes, 1959-1961)
Keely Smith (1 episode, 1960)
Additional Muppet Performer (1 episode, 1960)
Harry the Hipster (1 episode, 1959)
Stan Freberg (1 episode, 1961)
Themselves (uncredited) (19 episodes, 1955-1961)