Here's what I found.. I'm not sure if I got everyone from the golden age, but I got most of them...
Jim Henson
"Sam and Friends" (1955)
Frank Oz
"The Jimmy Dean Show" (1963)
Jerry Nelson
The Cube (1969)
Richard Hunt
he was on The Ed Sullivan Show (1971), but I don't know if individual puppeteers received screen credit.. if not, he started on Sesame Street the following year
Dave Goelz
The Muppets Valentine Show (1974)
Fran Brill
"Sesame Street" (1970)
Louise Gold
"The Muppet Show" (1977)
Steve Whitmire
The Muppets Go Hollywood (1979)
Caroll Spinney
"Bozo's Big Top" (1966)
Kevin Clash
"The Great Space Coaster" (1981)
Kathryn Mullen
"The Muppet Show" (1978)
... and just for fun:
Gerry Parkes
"The Forest Rangers" (1964)