Suggestions by @user_111056

Mickey Mouse

as 64 in Cartoon Brawlers

Conrad Vernon

as Producer in Dreamworks' Garfield

Tom McGrath

as Writer in Dreamworks' Garfield

Mike Myers

as Exterminator Jonathan Lewis in Dreamworks' Garfield

Jenifer Lewis

as Garfield's Aunt in Dreamworks' Garfield

Craig Robinson

as Garfield's Uncle in Dreamworks' Garfield

Renée Zellweger

as Liz in Dreamworks' Garfield

Cameron Diaz

as Arlene in Dreamworks' Garfield

Seth Rogen

as Garfield's Other Brother in Dreamworks' Garfield

Shane Richie

as Garfield's Brother in Dreamworks' Garfield

Ben Stiller

as Garfield's Father in Dreamworks' Garfield

Glenn Close

as Garfield's Mother in Dreamworks' Garfield

Tom Holland

as Nermal in Dreamworks' Garfield

Frank Welker

as Odie in Dreamworks' Garfield

Ewan McGregor

as Jon Arbuckle in Dreamworks' Garfield

Jack Black

as Garfield in Dreamworks' Garfield

Tim Rice

as Songs in Dreamworks' Garfield

Phil Lord and Christopher Miller

as Director in Dreamworks' Garfield

THX

as THX Logo in Snoopy And Friends: The Movie

Caillou

as Commander Caillou in Snoopy And Friends: The Movie