Suggestions by @kylewhite

Robert Simonds

as Producer in Scooby-Doo (1996)

Colin Wilson

as Producer in Scooby-Doo (1996)

Steve Barron

as Director in Scooby-Doo (1996)

Martin Short

as Emile Mondavarious in Scooby-Doo (1996)

Steve Martin

as Emile Mondavarious in Scooby-Doo (1996)

Carla Gugino

as Velma Dinkley in Scooby-Doo (1996)

David Spade

as Shaggy Rogers in Scooby-Doo (1996)

James Marsden

as Fred Jones in Scooby-Doo (1996)

Selma Blair

as Eve in Xena: Warrior Princess (1995-2001)

Martin Short

as Salmoneus in Xena: Warrior Princess (1995-2001)

Gabriel Byrne

as Julius Caesar in Xena: Warrior Princess (1995-2001)

Laura Dern

as Ephiny in Xena: Warrior Princess (1995-2001)

Eric Stoltz

as Iolaus in Xena: Warrior Princess (1995-2001)

Isla Fisher

as Aphrodite in Xena: Warrior Princess (1995-2001)

Christine Taylor

as Aphrodite in Xena: Warrior Princess (1995-2001)

Pierce Brosnan

as Ares in Xena: Warrior Princess (1995-2001)

Eddie Murphy

as Autolycus in Xena: Warrior Princess (1995-2001)

Scott Bakula

as Autolycus in Xena: Warrior Princess (1995-2001)

Jeff Goldblum

as Autolycus in Xena: Warrior Princess (1995-2001)

Drew Barrymore

as Callisto in Xena: Warrior Princess (1995-2001)