Suggestions by @jesselee

Bubble Bass

as Bubble Bass in Scooby Doo: Belle

Princess Bubblegum

as Princess Bubblegum in Scooby Doo: Belle

Carnage (Cletus Kasady)

as Carnage in Scooby Doo: Belle

Doctor Victor von Doom

as Doctor Doom in Scooby Doo: Belle

Queen of Hearts (song)

as Queen of Hearts in Scooby Doo: Belle

Mario (Nintendo Character)

as Super Mario in Scooby Doo: Belle

Princess Peach Toadstool

as Princess Peach in Scooby Doo: Belle

Marceline

as Marceline in Scooby Doo: Belle

King Koopa

as King Koopa in Scooby Doo: Belle

Alice (Disney)

as Alice in Scooby Doo: Belle

John Darling

as John Darling in Scooby Doo: Belle

Professor Owl

as Professor Owl in Scooby Doo: Belle

Michael Darling

as Michael Darling in Scooby Doo: Belle

Nibs

as Nibs in Scooby Doo: Belle

Slightly

as Slightly in Scooby Doo: Belle

Tootles

as Tootles in Scooby Doo: Belle

White Rabbit

as Whjte Rabbjt in Scooby Doo: Belle

FAKE

as The Mad Hatter in Scooby Doo: Belle

Queen of Hearts (Disney Heroes: Battle Mode)

as Queen of Hearts in Scooby Doo: Belle

The March Hare

as The March Hare in Scooby Doo: Belle