Tyrannosaurus rex

Tyrannosaurus rex was one of the most famous dinosaurs on Earth. They lived towards the end of the Cretaceous period. It was still one of the largest and most dangerous known land predators. (DW: Invasion of the Dinosaurs)

Earth species
The Tenth Doctor and Martha Jones encountered a T-rex when they visited prehistoric Earth. (QR: Made of Steel)

The Tyrannosaurus was one of several biological specimens taken into cryogenic suspension by the Silurians. The Silurian shelter under Wenley Moor used a Tyrannosaur as a defensive measure, releasing it into the nearby cave system where it killed at least one human. (DW: Doctor Who and the Silurians)

During the 1970s invasion of London, the Tyrannosaurus rex was one of the dinosaurs that was brought into the present. The T. rex was one of the most dangerous creatures encountered by the UNIT troops. Though not very bright, they seemed to be bullet-proof and could only be scared away with grenades. One was even shown breaking through a wall. These T. rexes were large, ponderous creatures with short legs, lumpy features and a thick tail. The Doctor encountered at least three T. rexes and captured one in order to find out where (or when) they came from. (DW: Invasion of the Dinosaurs)

In an alternate universe Tyrannosaurus rex was one of the creatures bought back from extinction by the silurians and were possiby used for mounts (NA: Blood Heat)

The Tenth Doctor brought a T-rex to 2008 to fight the Cybermen. It destroyed all of them. (QR: Made of Steel)

The Rani had several Tyrannosaurus rex embryos in her collection. These embryos were accidentally released after The Rani's TARDIS was sabotaged by the the Sixth Doctor. These embryos grew into greener, sleeker examples of T. rex than those previously encountered by the Doctor. (DW: The Mark of the Rani)

A zoo on an unnamed planet exhibited a tyrannosaurus or a tyrannosaurus-like creature. (TVC: 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. (BFA: The Five Companions)

A robotic T-Rex named Kevin briefly joined the Doctor as a companion, although his size and appearance caused complications.

Other planets
The Tyrannosaurs was 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 bit the Dalek's dalekanium casings in half and crush at least four Daleks with their massive feet. (DWBIT: #7)