Charlie Adler
Ickis (voice) (103 eps)
Christine Cavanaugh
Oblina (voice) (103 eps)
Gregg Berger
The Gromble (voice) (103 eps)
Beverly Archer
The Library Monster (voice) (103 eps)
Marcia Strassman
Harryette (voice) (103 eps)
David Eccles
Krumm / Snorch (voice) (102 eps)
Jim Belushi
Simon the Monster Hunter (voice) (102 eps)
Kath Soucie
Blorp 2+4 / Woman (voice) (102 eps)
Lacey Chabert
Girl (voice) (102 eps)
Michael Dorn
Borl / Chauffer (voice) (102 eps)
Bronson Pinchot
Deitrich Dunlap (voice) (102 eps)
Tim Curry
Zimbo (voice) (102 eps)
Shelley Duvall
Ocka (voice) (102 eps)
Edward Winter
Dr. Buzz Kutt (voice) (102 eps)
Billy Vera
Slickis (voice) (102 eps)
Bill Fagerbakke
Carl (voice) (102 eps)
Brock Peters
The Pool (voice) (2 eps)
Susan Blu
Mom / Hair / Kid 4 (voice) (1 eps)
Aaron Michael Metchik
Kid 3 / Kid 6 (voice) (1 eps)
Erik von Detten
Vic / Tough Kid (voice) (1 eps)
Jarrett Lennon
Kid 1 (voice) (1 eps)
George Segal
J.B. (voice) (1 eps)
Andrea Martin
Gromble's Mom (voice) (1 eps)
Ian Ziering
Gludge (voice) (1 eps)
Bruce Weitz
Luxor (voice) (1 eps)
Fyvush Finkel
Jackie the Shtickman (voice) (1 eps)
Sven-Ole Thorsen
Lars Halverson (voice) (1 eps)
Arthur Burghardt
Elban Bigfoot (voice) (1 eps)
Taj Mahal
Ellis Robinson (voice) (1 eps)
John Pankow
Blook the Granfaloon (voice) (1 eps)
William Hootkins
Loch Ness Monster (voice) (1 eps)
Keith Szarabajka
Skritch (voice) (1 eps)
Mark DeCarlo
Pitch Monster (voice) (1 eps)
Stuart Whitman
Mule Morgan (voice) (1 eps)
Norbert Weisser
Farfegnuton (voice) (1 eps)
Jason Graae
Z-12 (voice) (1 eps)
David Workman
X-14 (voice) (1 eps)
Mitzi McCall
Custodian Monster (voice) (1 eps)
Peter Bonerz
Sal (voice) (1 eps)
Conchata Ferrell
Simpah (voice) (1 eps)
John Rhys-Davies
Head Judge / Zifdo (voice) (1 eps)
Cynthia Mann
Dizzle (voice) (1 eps)
Kevin Michael Richardson
Clem Lashinsky / Zooeuh (voice) (1 eps)
Kevin McBride
Car Wash Man / Skater #1 (voice) (1 eps)
Candi Milo
Splazu / Skater #2 (voice) (1 eps)