Denim
Denim was a strong fabric.
Rose Tyler sometimes wore denim jeans. (TV: Rose, The End of the World, Aliens of London/World War Three, Dalek, Fear Her, etc) She also sometimes wore denim jackets. (TV: Father's Day, Boom Town, Fear Her) She once wore a denim mini skirt (TV: Boom Town), and also wore short denim dungarees. (TV: Tooth and Claw)
Sarah Jane Smith tended to wear denim jeans. (TV: School Reunion, onwards)
Martha Jones tended to wear denim jeans. (TV: Smith and Jones, The Shakespeare Code, Gridlock, Daleks in Manhattan/Evolution of the Daleks, The Lazarus Experiment, The Sound of Drums/Last of the Time Lords)
Donna Noble sometimes wore denim jeans. (TV: Planet of the Ood, Silence in the Library/Forest of the Dead, Turn Left, The Stolen Earth/Journey's End, The End of Time)
Amy Pond wore denim mini-skirts. (TV: Victory of the Daleks, The Vampires of Venice, Curse of the Black Spot; GAME: City of the Daleks, Blood of the Cybermen, TARDIS, Shadows of the Vashta Nerada) She also wore skinny denim jeans, (TV: The Impossible Astronaut) and sometimes a denim jacket. (TV: Let's Kill Hitler)
Maria Jackson wore navy blue overalls when she moved to Bannerman Road. (TV: Invasion of the Bane) She wore denim jackets and denim jeans. (TV: Eye of the Gorgon, onward) She sometimes wore a denim mini-skirt. (TV: Warriors of Kudlak)
Bliss wore a denim jacket. (AUDIO: State of Bliss)
Kathy Nightingale wore denim jeans. (TV: Blink)
Rani Chandra wore denim jackets. (TV: The Temptation of Sarah Jane, The Mad Woman in the Attic, etc.)
Clara Oswald wore a denim shirt when she and the Twelfth Doctor first met Ashildr. (TV: The Girl who Died)
Yasmin Khan wore denim jackets. (TV: The Witchfinders, Can You Hear Me?)
Jack Harkness purchased denim jeans from a Topshop in Cardiff. Trine-E and Zu-Zana called it a "design classic", but considered it dated by the year 200,100. (TV: Bad Wolf)