Tyrannosaurus rex

Tyrannosaurus rex was one of the most famous dinosaurs on Earth. It was also known as the T. rex, or king tyrant lizard. (AUDIO: The World Traders)

They lived towards the end of the Cretaceous period. It was one of the largest and most dangerous known land predators. (TV: Invasion of the Dinosaurs)

History
The Twelfth Doctor, Sonny Robinson, and Val Kent encountered a Tyrannosaurus rex during a visit to the Jurassic Era. (COMIC: Invasion of the Mindmorphs)

According to one account, the Tyrannosaur-like creature that guarded the Silurian caves in Wenley Moor was in fact a Tyrannosaurus rex. (PROSE: Doctor Who and the Cave-Monsters). However, another account suggested that this was a species genetically created by the Silurians themselves, with the Doctor stating that he did not recognise it from the Mesozoic age. (TV: Doctor Who and the Silurians) However, another attack pet kept by a different hibernation facility, located in London beneath Hyde Park, was in fact a Tyrannosaur. It was accidentally awakened in Vastra's Victorian London alongside the Triad ruling the facility, but the Twelfth Doctor later gave it a lift in the TARDIS back to the age of the dinosaurs — Canada sixty-six million years prior, to be exact. Vastra stated that she approved, having never liked the practice of "keeping wild animals as pets" in which some of her kind indulged. (GAME: Lost in Time)

During Operation Golden Age, Tyrannosaurus rex was one of the dinosaurs that was brought into the present through time eddys. The Third Doctor attempted to catch one and Mike Yates stunned it using a special gun. UNIT transported it to a hangar where it was chained up. The Doctor intended to monitor it so that he could trace the source of the dinosaur appearances. However, General Finch broke its chains and it escaped, smashing through a wall before returning to its own time. The devices used to monitor it were sabotaged, leaving the Doctor without any readings. (TV: Invasion of the Dinosaurs)

had several Tyrannosaurus rex embryos in her collection. These embryos were accidentally released after the Rani's TARDIS was sabotaged by the Sixth Doctor. Due to time spillage, these embryos then quickly grew into a greener, sleeker example of T. rex than those later encountered by the Doctor. (TV: The Mark of the Rani)

While on a short field trip to the Jurassic era, the Tenth Doctor and Martha Jones encountered and escaped a T. rex. Later, the Doctor opened a space-time portal between 2008 and the moment and location that the TARDIS had dematerialized. This caused the lunging T. rex to emerge in the present and attack the Cybermen, destroying two of them and dragging the remains of one back with it to the dinosaur's own time. The Doctor suggested that since the Cyberman would be hard for the T. rex to digest, it would probably drop bits of it all around the Jurassic period. The Doctor was amused by the idea that this would keep archaeologists guessing when they uncovered the Cyberman pieces. (PROSE: Made of Steel)

Tyrannosaurus rex was among the dinosaurs farmed by the Sanctified Empire. The Sanctified sent one T. rex to Cardiff in 2008 with a Harrowkind and several other dinosaurs to try and stop Vox. But Vox used the absorbed power of the Cardiff Space-Time Rift to obliterate the T. rex. (COMIC: Rift War!)

Several Tyrannosaurus rex were brought into Sydney Australia in 2010 by a chronal wave. They wreaked havoc in the city, then presumably died for freezing temperatures when another chronal wave brought the Ice Age into Sydney. (COMIC: The Age of Ice)

Tyrannosaurus rex was among the specimens placed aboard the Silurian Ark by the Silurians with which to repopulate the Earth once the incorrectly predicted catastrophe passed. When the Eleventh Doctor and his companions arrived on the Ark in 2367, they found a T. rex nest and a sleeping juvenile. (TV: Dinosaurs on a Spaceship)

A zoo on an Earth-like planet exhibited a Tyrannosaurus rex or a tyrannosaurus-like creature. (COMIC: The Didus Expedition)

A Tyrannosaurus rex was transported to an alternative Death Zone on Gallifrey, where it proceeded to kill several Daleks before itself being exterminated. (AUDIO: The Five Companions)

A robotic Tyrannosaurus named Kevin briefly joined the Eleventh Doctor as a companion, although his size and appearance caused complications. (COMIC: When Worlds Collide, Your Destiny Awaits, Space Squid)

Other timelines
On the Silurian Earth, Tyrannosaurus rex was one of the creatures bought back from extinction by the Silurians and were occasionally used for mounts. (PROSE: Blood Heat)

Behind the scenes

 * According to non-narrative material in DWBIT 7, Tyrannosaurs were also native to the planet Raxas, and, along with the other Raxas dinosaurs, proved to be more than a match for a Dalek attack. They were so strong they could bite the Dalek's dalekanium casings in half and crush at least four Daleks with their massive feet.
 * Many reference sources identify the Theropod Silurian pet from TV: Doctor Who and the Silurians as a T. rex. However, whilst this is indeed the case in the novelisation, it is very unlikely going by televised evidence, since the Doctor claims not to recognise the species, the implication there being that the species is one bred or engineered by the Silurians, which would mean whatever species it may be would not exist in the real world.
 * The T. rex is amongst the most iconic of real-world Dinosaurs, explaining its prominent featuring in Doctor Who
 * In real life, the T. rex existed in the Cretaceous period, however most DWU sources date it to the Jurassic.