Background Pony #D251
Sunset Shimmer: Corruted herself by absorbing Magic Element's magic while being on Earth
Dazzlings: Not corrupted, just their natural magic.
Midnight Sparkle: Corrupted by absorbing Earth-version of Equestrian magic
Post-portal crack: any artifacts enchanted by Earth-version of Equestrian magicisare forcibly feeding user their magic
Gaia Everfree: corrupted by using artifact enchanted by Earth-version of Equestrian magic
Juniper Monstar: corrupted by using artifact enchanted by Earth-version of Equestrian magic
Human Twilight Sparkle: not corrupted by enchanted watering-can, either because it wasn't used enough, or because she already overcome monstrofication phase into friendship phase
Wallflower Blush: not corrupted, because artifacts enchanted in Equestria are self-contained and do not forcibly feed user any magic
Vignette Valencia: started being corrupted by using artifact enchanted by Earth-version of Equestrian magic, but never reacted monstrofication phase, because she was reformed before that.
PostCrush: not corrupted, because artifacts enchanted in Equestria are self-contained and do not forcibly feed user any magic
Moral of the story: never use artifacts that were enchanted in Earth. Never try to absorb magic from Equestrian aftifact while being on Earth. Even if you're not being corrupted magically, too much power can twist you psychologically (Wallflower Blush, PostCrush).
Dazzlings: Not corrupted, just their natural magic.
Midnight Sparkle: Corrupted by absorbing Earth-version of Equestrian magic
Post-portal crack: any artifacts enchanted by Earth-version of Equestrian magic
Gaia Everfree: corrupted by using artifact enchanted by Earth-version of Equestrian magic
Juniper Monstar: corrupted by using artifact enchanted by Earth-version of Equestrian magic
Human Twilight Sparkle: not corrupted by enchanted watering-can, either because it wasn't used enough, or because she already overcome monstrofication phase into friendship phase
Wallflower Blush: not corrupted, because artifacts enchanted in Equestria are self-contained and do not forcibly feed user any magic
Vignette Valencia: started being corrupted by using artifact enchanted by Earth-version of Equestrian magic, but never reacted monstrofication phase, because she was reformed before that.
PostCrush: not corrupted, because artifacts enchanted in Equestria are self-contained and do not forcibly feed user any magic
Moral of the story: never use artifacts that were enchanted in Earth. Never try to absorb magic from Equestrian aftifact while being on Earth. Even if you're not being corrupted magically, too much power can twist you psychologically (Wallflower Blush, PostCrush).