Two-Headed Monster (right half), Forgetful Jones (1981–1991), Gladys the Cow, Sully, Don Music, Placido Flamingo, Elmo (1984–1985), Sonny Friendly, Ferlinghetti Donizietti (1980–1984), Aristotle, Leo the Party Monster, Dip Cat, Brad, Timmy Twiddlebug, Captain Vegetable, Gilbert, Dr. Kvetch, Richard, Zero, Spaceship Surprise Mate, Worby the Grouch, Earl, Green Alphabeat, The Beetles' Lead Singer, Tarnish Brother, Grandpa Count, Grandpa Grouch, Larry Rhymie (1978), Mrs. Bolinski (1982), Tough Eddie (1984), Frazzle (1989), Harvey Monster (occasionally), Maurice Monster (occasionally), Yip Yip Martian, Mr. Snuffleupagus (back half, 1970s), Slimey the Worm (1978), Various