Belt

A belt was a strip of leather or other fabric worn, typically round the waist, to support or hold in clothes or to carry weapons.

Worn by the Doctor

Some versions of the Doctor wore belts.

The Eighth Doctor had his tan trousers haphazardly secured by a slouching belt only buckled by an S-link chain, (COMIC: The Pictures of Josephine Day, A Matter of Life and Death, The Lost Dimension; AUDIO: He Kills Me, He Kills Me Not) right to his fall on Karn. (TV: The Night of the Doctor)

The War Doctor wore the Eighth Doctor's belt with the S-link chain for some time. (TV: The Night of the Doctor; AUDIO: Light the Flame; WC: Doctors Assemble) He mostly wore a box-frame belt with several fastener pins and studded pinholes, (COMIC: The Clockwise War, Ambush, The Lost Dimension, The Whole Thing's Bananas, First Rule, The Organ Grinder, Kill God, Fast Asleep, Four Doctors; AUDIO: The Innocent; PROSE: Engines of War) up to his death after the 1562/2013 Zygon Invasion of Earth and the Fall of Gallifrey. (TV: The Day of the Doctor)

The Ninth Doctor wore a black leather belt. (TV: Dalek)

A feminine version of the Doctor with a bald head and dark skin wielding a flaming sword wore a belt. (PROSE: Rose)

The Curator, a future version of the Doctor in the form of an older Fourth Doctor, wore a black belt. (COMIC: The Then and the Now)

Worn by Companions

Rose Tyler wore a brown belt. (TV: The Christmas Invasion)

Oswin Oswald wore a black belt. (TV: Asylum of the Daleks)

Peri Brown wore belts in plain blue, (TV: Attack of the Cybermen) or red. (TV: Vengeance on Varos)

Donna Noble wore a dark brown belt. (TV: Silence in the Library|Forest of the Dead, Turn Left, The Stolen Earth|Journey's End)

Romana II wore a cherry belt when she enjoyed punting, (TV: The Five Doctors [+]) and when she met Skagra and Professor Chronotis. (TV: Shada [+])

Jenny wore a khaki belt. (TV: The Doctor's Daughter)

River Song wore a brown belt to carry firearms. (TV: Silence in the Library|Forest of the Dead, The Pandorica Opens|The Big Bang, The Impossible Astronaut)

Worn by the Master

The Tremas Master wore a belt with a dragon-themed buckle during his Survival Stratagem. (TV: Survival)

The Spy Master wore belts with his costumes. (TV: Spyfall)

Worn by Others

The Sontarans wore belts with weapons and translating devices. (TV: The Time Warrior, The Sontaran Experiment, The Invasion of Time, The Two Doctors, The Sontaran Stratagem|The Poison Sky, The Last Sontaran, Enemy of the Bane, The End of Time, The Pandorica Opens, A Good Man Goes to War, The Crimson Horror, The Time of the Doctor, Deep Breath, War of the Sontarans, Survivors of the Flux|The Vanquishers; AUDIO: The Sontarans, Heroes of Sontar, The First Sontarans, Terror of the Sontarans, The Sontaran Ordeal, The Eternity Cage; PROSE: Lords of the Storm, Shakedown, The Sontaran Games, The Taking of Chelsea 426; GAME: The Gunpowder Plot; HOMEVID: Shakedown: Return of the Sontarans)

Graham O'Brien observed that Ribbons had a belt full of massive dead rats with six legs. (TV: It Takes You Away)