SesameStreetFan said:
I thought of another one as well. But with this one, it's really splitting hairs.
Fat Blue: Jim Henson (First Season only) Jerry Nelson (1970-2006) David Rudman (For one line In the movie Elmo in Grouchland)
Actually, Jim Henson did perform Fat Blue in some skits after the first season. He performed Fat Blue in the Alphabet Song with Lena Horne (this skit had a red background, as opposed to the dark white background that seemed to be the only background color, with the occasional exception of black, used in the first season, and it also featured Farley, who debuted in season two, and it sounds like Richard Hunt sang back-up vocals, and he first performed on Sesame Street in either the third or fourth season). Henson also performed Fat Blue in the Clap, Clap, Clap song (which featured a bright green background and featured such post-season one characters as Farley, Roosevelt Franklin, Roosevelt Franklin's mother, and I think Prairie Dawn).