Chaotix (Knuckles' Chaotix)
Starfleet (Star Trek)
Order of the White Lotus (Avatar: The Last Airbender)
The Dark Masters (Digimon Adventure)
Cobra (G.I. Joe)
Organization Without a Cool Acronym (Phineas and Ferb)
Aperture Science (Portal)
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You know what they say: If you can't beat them, join them. If you can't join them, burn their house to the ground!