Suggestions by @nosetwice

Michael Peña

as Plumpy in Cartoon World: The Series (Candyland)

+4-1Score: +3

Christopher Lloyd

as Nicodemus in Rats of NIMH (2024)

+4-0Score: +4

Grey DeLisle

as Rarity/Princess Luna/Flurry Heart (voice) in Journey into Space: A My Little Pony Movie

+5-2Score: +3

Kelsey Grammer

as Mermaid Man in SpongeBob SquarePants

+5-0Score: +5

Kelsey Grammer

as Mad Scientist in Mermaid Man and Barnacle Boy

+3-1Score: +2