Suggestions by @madysonroth

Manny Rivera

as Tony Tiger in Foodfight: BETTER EDITION

Score: +6

Matt Groening

as Director in The Itchy and Scratchy Movie

Score: +8

Tara Strong

as Timmy Turner the 69th in An Ultimatlly big problem

Score: +5

Carlos Alazraqui

as Grandpapi in An Ultimatlly big problem

Score: +3

Eric Bauza

as Big chungus in An Ultimatlly big problem

Score: +4

Tom McGrath

as Skipper in An Ultimatlly big problem

Score: +5

Quinton Flynn

as Sheldon in El Tigre: The Sh*tpost Strikes Back again

Score: +3

Grey DeLisle

as Frida in An Ultimatlly big problem

Score: +2

Karen Gillan

as Mitosis in An Ultimatlly big problem

Score: +3

Charles Martinet

as Giuseppe in The Super Mario Bros. Movie (2003)

Score: +3

Chip Zien

as Howard the Duck in An Ultimatlly big problem

Score: +2

Chris Pratt

as Mario in An Ultimatlly big problem

Score: +3

Alanna Ubach

as Manny rivera in An Ultimatlly big problem

Score: +2

Janice Kawaye

as Jenny wakeman in An Ultimatlly big problem

Score: +3

Frank Welker

as Garfield in An Ultimatlly big problem

Score: +3

Billy West

as Toad in The Super Mario Bros. Movie (2003)

Score: +1

Charlie Day

as Luigi in The Super Mario Bros. Movie (2003)

Score: +4

Jennifer Tilly

as Princess Peach in The Super Mario Bros. Movie (2003)

Score: +9

Jack Black

as Bowser in The Super Mario Bros. Movie (2003)

Score: +3

James Marsden

as Mario in The Super Mario Bros. Movie (2003)

Score: +10