Nazis are villains no matter what context you use them in. I did a whole list of this thing once.
Armand--Lestat
Ralph Nickleby, Sir Mulberry Hawk, and Wackford Squeers--Nicholas Nickleby
Claudius--Hamlet
Iago--Othello
Javert and Thenardier--Les Miserables
Sweeney Todd, Mrs. Lovett, and Judge Turpin
Velma and Amber Von Tussle--Hairspray
Edmund and Goneril and Regan--King Lear
Roy Cohn--Angels in America
Edward Hyde--Jekyll and Hyde
Those two Scottish people--The Scottish Play
Audrey II and Orin--Little Shop of Horrors (Mushnik isn't so much a villain as a total douchebag)
The Wicked Witch of the West--The Wizard of Oz (then everyone sees Wicked and pummels Mattbrain to death for saying so)
Richard III--goes without saying
Mr. Potter--It's A Wonderful Life
Don John--Much Ado About Nothing
J.J. Hunsecker--The Sweet Smell of Success
Margaret--Henry VI
Marie Esposito--The Most Happy Fella
Zoser--Aida
Jud Fry--Oklahoma
Curtis Taylor Jr.--Dreamgirls
Benny--Rent
Gaston--Beauty and the Beast
Chauvelin--The Scarlet Pimpernel
Miss Hannigan--Annie
Arkadina--The Seagull
Scar--The Lion King
Madame Morrible--Wicked
Glen Guglia--The Wedding Singer
Thuy--Miss Saigon
The Media--Floyd Collins
Hugh Dorsey and Tom Watson--Parade
Willie Conklin--Ragtime
The Warden--Kiss of the Spider Woman
Mayor Shinn and Charlie Cowell--The Music Man
Killer Queen and Khashoggi--We Will Rock You
Racism and general intolerance--A helluva lotta shows
Butters, go buy World of Warcraft, install it on your computer, and join the online sensation before we all murder you.
--Cartman: South Park
ATTENTION FANS: I will be played by James Barbour in the upcoming musical, "BroadwayWorld: The Musical."