Wool

Wool was a type of soft curly or wavy hair forming the coat of a sheep, goat, llama, alpaca, or yak; especially when shorn and prepared for use in making cloth or yarn:

The Sixth Doctor's coat featured patches of peach wool. (TV: The Twin Dilemma-Time and the Rani) His successor, the Seventh Doctor, had this before switching for a silver grey safari jacket. (TV: Time and the Rani-The Greatest Show in the Galaxy)

Wool was used to make greatcoats including the navy blue one one worn by Captain Jack Harkness. (TV: The Empty Child, onwards) It was also used to make overcoats including the one worn by the Half-Face Man. (TV: Deep Breath)

Wool was used for the lining of clothes including the frock coat of wine purple moleskin worn by the Eleventh Doctor, (TV: The Snowmen) the overcoat worn by Professor Jericho, (TV: Survivors of the Flux) and the ebony leather jacket including the one worn by Ruby Sunday. (TV: The Church on Ruby Road)

Wool made scarves such as those worn by the Doctor's first, (TV: An Unearthly Child) fourth, (TV: Robot) seventh, (TV: Time and the Rani), war, (TV: The Day of the Doctor) eleventh, (TV: The Snowmen) and thirteenth incarnations, (TV: Resolution) and a parallel version called the Warrior; (AUDIO: The Difference Office)  as well as companions including Rose Tyler, (TV: Boom Town) Donna Noble, (TV: Turn Left) Amy Pond, (TV: The Pandorina Opens) Romana II, (TV: Destiny of the Daleks) and Helen Sinclair; (AUDIO: The Red Lady) and also by others including Sally Sparrow, (TV: Blink) Petronella Osgood, (TV: The Day of the Doctor) Professor Jericho, (TV: Survivors of the Flux) and the Spy Master. (TV: The Power of the Doctor)

Wool was used to make jumpers, sweaters, and sweater vests including those worn by the Doctor's fifth, (TV: Castrovalva) seventh, (TV: Time and the Rani) ninth, (TV: Rose) twelfth, (TV: The Return of Doctor Mysterio), thirteenth, (TV: Spyfall) and fifteenth incarnations; (TV: The Church on Ruby Road) and also those worn by companions including Barbara Wright, (TV: The Web Planet), Sarah Jane Smith, (TV: The Monster of Peladon) Martha Jones, (TV: The Sontaran Stratagem) Donna Noble, (TV: Turn Left) Amy Pond, (TV: Dinosaurs on a Spaceship) Yasmin Khan, (TV: The Woman Who Fell to Earth), Leela, (TV: Horror of Fang Rock) Jo Grant, (TV: Terror of the Autons) Rose Noble, (TV: The Star Beast), Brigadier Alistair Gordon Lethbridge-Stewart, (TV: The Claws of Axos) Zoe Heriot, (TV: The Mind Robber) Liz Shaw, (TV: Doctor Who and the Silurians) and Ruby Sunday; (TV: The Church on Ruby Road) and by more including Petronella Osgood, (TV: The Zygon Inversion) Sally Sparrow, (TV: Blink) Emma Grayling, (TV: Hide) and the Spy Master. (TV: The Power of the Doctor)