Violet

Violet was a shade of purple. It was situated on one end of the visible spectrum before indigo and blue. (TV: Sky)

Fashion
The Eighth Doctor wore a violet waistcoat when he first met Stacy Townsend during an encounter with Cybermen on the Dreadnought. (COMIC: Dreadnought)

Rose Tyler wore an asymmetrical, patchwork blouse, mostly violet. (TV: New Earth; AUDIO: Infamy of the Zaross, The Sword of the Chevalier)

Martha Jones wore a violet tank-top. (TV: Last of the Time Lords),

Donna Noble wore a violet top under her gunmetal grey sweater dress. (TV: Turn Left, The Stolen Earth/Journey's End)

The Fourth Doctor wore a crimson scarf with violet stripes, (TV: The Leisure Hive) up to his death. (TV: Logopolis)

The Sixth Doctor wore a plain violet waistcoat. (COMIC: Endgame)

wore a violet suit when she and Clara Oswald went to Skaro. (TV: The Magician's Apprentice/The Witch's Familiar)

The Eleventh Doctor wore a violet bow tie. (TV: The Bells of Saint John)

As CEO of 24 Carat, Melanie Bush wore a violet skirt suit. (WC: 24 Carat)

Yasmin Khan wore a violet t-shirt when she went to Punjab during 1947. (TV: Demons of the Punjab)

The Curator, taking the form of an older Sixth Doctor, wore a violet frock coat with a silver cat brooch. (AUDIO: Crossed Lines)

Other
In 2009, apples in Mr. Cousins' greengrocers were turned violet by a broken Filbik device. (PROSE: The End of the Rainbow)

Raxacoricovarlonpatorians had violet skin. (COMIC: Doctormania)

The Maelstrom was partially violet. (PROSE: Enter Wildthyme)