Black

Black was a colour.

Clothing
The Master usually dressed in mostly black clothes. (TV: Terror of the Autons, Frontier in Space, The Deadly Assassin, The Keeper of Traken, Doctor Who, Utopia, Last of the Time Lords, The End of Time, The Doctor Falls, Spyfall)

Davros wore a black lab tunic. (TV: Genesis of the Daleks, Destiny of the Daleks, Resurrection of the Daleks, Revelation of the Daleks, Remembrance of the Daleks, The Stolen Earth, Journey's End, The Magician's Apprentice, The Witch's Familiar; AUDIO: The Juggernauts, et al.)

Black Daleks were identified by their black casing s. (COMIC: Duel of the Daleks, TV: The Dalek Invasion of Earth, The Chase, The Dalek's Master Plan, Resurrection of the Daleks, Remembrance of the Daleks, AUDIO: The Juggernauts, Brotherhood of the Daleks, The Apocalypse Element, et al.) Dalek Sec had a completely black casing. (PROSE: Birth of a Legend, TV: Army of Ghosts/Doomsday, Daleks in Manhattan/Evolution of the Daleks)

Cyber Leaders were identified by their black head handlebars. (TV: Earthshock, The Five Doctors, Attack of the Cybermen, Silver Nemesis, Army of Ghosts/Doomsday, The Pandorica Opens, et al.)

The Voord wore black bodysuits. (TV: The Keys of Marinus)

The Trickster normally wore a long black hooded robe and gloves. (TV: Whatever Happened to Sarah Jane?, The Temptation of Sarah Jane Smith, The Wedding of Sarah Jane Smith)

The Ninth Doctor normally wore all black articles of clothing, save for a long sleeve jumper of a different colour, (TV: Rose et al.) though by the end of his life even the jumper he wore was black. (TV: Bad Wolf/The Parting of the Ways)

The First Doctor wore a black town coat. (TV: An Unearthly Child, The Daleks, Marco Polo, The Dalek Invasion of Earth, The Chase, The Dalek's Master Plan, The Tenth Planet, The Three Doctors, The Five Doctors, Twice Upon A Time et al.)

The War Doctor wore a double-breast leather trenchcoat. (COMIC: The Whole Thing's Bananas)

The Eleventh Doctor wore a black moleskin overcoat. (TV: A Town Called Mercy)

The Twelfth Doctor wore a black velvet frockcoat. (TV: The Pilot, Thin Ice, World and Enough/The Doctor Falls, Twice Upon A Time, et al.)

The Thirteenth Doctor wore a black tuxedo and bow tie. (TV: Spyfall)

Clara Oswald wore a black leather jacket on occasion. (TV: The Magician's Apprentice/The Witch's Familiar)

Gwen Cooper wore a black blouse. (TV: Day One)

Toshiko Sato wore a black t-shirt. (TV: Cyberwoman)

Sarah Jane Smith wore a black leather jacket. (TV: The Monster of Peladon, School Reunion)

Some individuals wore black lipstick. (PROSE: No Future, Goth Opera, Dry Pilgrimage)

In Through the Eye of Eternity, the Black Eye of Eternity generally symbolised that the week's episode would be a black comedy. One fan wearing a black Eye pin, an apprentice mortician in Shoestring, Indiana, was fired after laughing at a client's sombre remark. (PROSE: The Book of the War)

Biology
The Second Doctor had black hair. (TV: The Tenth Planet)

The Host of the Lupine Wavelength Haemovariform had all-black eyes. (TV: Tooth and Claw) Grace Holloway's eyes turned all-black when she was controlled by. (TV: Doctor Who) Mercy Hartigan's eyes turned all-black when she was converted into the CyberKing. (TV: The Next Doctor) Owen Harper's eyes turned all-black when he was possessed by Death. (TV: Dead Man Walking)

Nostrovites had black blood, (TV: Something Borrowed) as did the Process. (PROSE: Cat's Cradle: Time's Crucible)

Black roses grew on Florana. (AUDIO: The Elite)