Brown

The War Doctor had brown hair when he was younger. (COMIC: The Clockwise War)

Brown was a colour.

Biology

Numerous incarnations of the Doctor had brown coloured hair. Among them were younger versions of the First Doctor, (COMIC: Vortex Butterflies) and the War Doctor. (TV: The Night of the Doctor) Other incarnations with brown hair include the Fourth, (TV: Planet of the Spiders) Seventh, (TV: Time and the Rani) Eighth, (TV: Doctor Who) Ninth, (TV: Rose) Tenth, (TV: The Parting of the Ways) Eleventh, (TV: The End of Time) and Fourteenth Doctors. (TV: The Power of the Doctor)

Many of their companions possessed brown hair, some being Peri Brown, (TV: Planet of Fire) Clara Oswald, (TV: The Bells of Saint John) Sarah Jane Smith, (TV: The Time Warrior) Rory Williams (TV: The Eleventh Hour) and Jack Harkness. (TV: The Empty Child)

Other individuals or species that had brown eyes included the Tactires, (COMIC: The Forgotten) Marnal, (PROSE: The Gallifrey Chronicles) Jane McKillen and Dale Hicks. (TV: Fear Her)

Sarah Jane Smith described the Uvodni, Uvlavad Kudlak, as having a "brownish" face. (TV: Warriors of Kudlak)

Fashion

Lucifer wore a brown parka and black hat. (WC: Mission: Find Lilith ^[+]Loading...["Mission: Find Lilith (webcast)"])

One of the two main suits the Tenth Doctor wore during this incarnation was dark brown with blue pinstripes. (TV: The Christmas Invasion)

Other

In Through the Eye of Eternity, the Brown Eye of Eternity only appeared once, in the 1996 episode "Miss Hiroshima". (PROSE: The Book of the War)