Bright Purple — The Heart, since Graceful Ladies Like Purple, and another alternative heroine color. Very popular with witches and other Magical girls.
Browns and other earthy tones — Nature Hero, Closer to Earth, The Mentor, Retired Badass; their use by villains is not unheard of but somewhat rare, and tends to denote a villain that relies on savagery and physical brutality over cunning.
Off-white — A jackass. Always takes the form of an ugly suit (or, if really bad, tuxedo), as it was fashionable for a time in social groups usually perceived as obnoxious, which is also when the trope is most often invoked, although guidos and arsim are sometimes dressed in particularly egregious examples in modern media.
Purple/Violet — Evil bitches and villainesses. Popular in Japanese media; the official color of videogame evil; really popular for comic book villains and nefarious aliens, particularly in combination with green. It is also often associated with venom. As it is also the ancient color for royalty, tying it in with Aristocrats.
Grey — Grayscale of Evil, soul-less, ego-extinct, card-carrying sociopathic monsters. Also popular for Mooks. note in Harry Harrison's work, the Grey Men are a race of cold emotionless mind-manipulators, all humanity and feeling having drained out of them.