Suggestions by @jesselee

Panic

as Panic in Scrappy-Doo: The Movie

Eeyore

as Eeyore in Scrappy-Doo: The Movie

Tigger

as Tigger in Scrappy-Doo: The Movie

Hades (Disney)

as Hades in Scrappy-Doo: The Movie

The Joker (Character)

as The Joker in Scrappy-Doo: The Movie

Harley Quinn (Dr. Harleen Quinzel)

as Harley Quinn in Scrappy-Doo: The Movie

Buzz Lightyear

as Buzz Lightyear in Scrappy-Doo: The Movie

Lex Luthor

as Lex Luther in Scrappy-Doo: The Movie

The Joker and Harley Quinn

as The Joker and Harley Quinn in Scrappy-Doo: The Movie

Grubs

as Grubs in Scrappy-Doo: The Movie

Batman

as Batman in Scrappy-Doo: The Movie

Emperor Zurg

as Emperor Zurg in Scrappy-Doo: The Movie

Mr. Smee

as Mr. Smee in Scrappy-Doo: The Movie

The Headless Horseman

as The Headless Horseman in Scrappy-Doo: The Movie

Captain Hook

as Captain Hook in Scrappy-Doo: The Movie

Starfire (Koriand'r)

as Starfjre in Scrappy-Doo: The Movie

Raven (Rachel Roth)

as Raven in Scrappy-Doo: The Movie

Veruca Salt

as Vercua Salt in Scrappy-Doo: The Movie

Marceline

as Marceline in Scrappy-Doo: The Movie

Princess Bubblegum

as Princess Bubblegum in Scrappy-Doo: The Movie