Jack Harkness once recalled an encounter with a six foot tall creature with big white tusks. (TV: Boom Town)
Species with tusks included Aggedors (TV: The Curse of Peladon) boars, (AUDIO: The Stuff of Nightmares) Pellonians, (AUDIO: The Paradise of Death) Rills, (TV: Galaxy 4) Saurians, (PROSE: Lords of the Galaxy) Tanik's species (PROSE: Wish You Were Here) and Thijarians. (TV: Demons of the Punjab)
In the state of reality before the Time Lords created history, there existed cities with buildings carved into gigantic ivory tusks that sprouted from the ground in mile high arches. (PROSE: Christmas on a Rational Planet)