A classic in the franchise and the animal most people think of first when they hear the word "dinosaur." The Tyrannosaurus appears in the Fallen Kingdom a few times. In the opening scene, it makes itself known in true horror-film fashion by hunting from the shadows and consuming a technician and in the scenes that follow, she saves the day. Once by saving Owen from another carnivore and again by eating the film's antagonist (an unorthodox way of defeating a villain but effective).
T-Rex was a dinosaur that existed during the Late Cretaceous period between 68-66 million years ago. While it is believed to have fed on herbivorous dinosaurs, experts are currently debating whether or not it was an apex predator or a simple scavenger. Jurassic Park (directed by Steven Spielberg) stated that T-Rex could reach speeds of up to 40km/h which is supported by real life research, though debated amongst experts.
The Velociraptor returns with its new design in Fallen Kingdom, although we're limited to just one this time in the form of Blue. She has a more prominent role in this film as pretty much the sole reason Owen (Chris Pratt) joins Claire's (Bryce Dallas Howard) rescue mission and later as the hero that once again defeats the hybrid reptilian monster.
Even though the basics are right: it had-- like all dromaeosaurs-- two long, curved claws, the Jurassic Park franchise's depiction of Velociraptors are known to be incorrect. Aside from the fact that they had feathers, in actuality, velociraptors were, like many species of dromaeosaur, much smaller at about 1.6ft in height. About the size of medium-sized dog. While the creature depicted on film is actually an amalgam of Velociraptor and Deinonychus (which was just slightly larger), it bears closer resemblance to Utahraptor, which was discovered after the release of Jurassic Park and reached heights of up to 5.5ft, the largest dromaeosaurid. Considering their appetite, teeth and claws, their size doesn't make them any less frightening.
When the rescue team finally reaches the ruins of the Jurassic World theme park, the first dinosaur they see is a massive Brachiosaurus. Aside from that one relatively peaceful scene, we see Brachiosaurus running from disasters or escaping from prisons. The film cleverly uses their whale-like call to evoke emotion, especially in an early powerful scene featuring a Brachiosaurus slowly being consumed by lava.
Brachiosaurus was a herbivorous sauropod that existed approximately 150 million years ago, one of the few dinosaurs in the Jurassic Park franchise that's actually from the Jurassic period. It was one quite a large sauropod (far from the largest) with a length spanning 85ft and a height of about 50ft (give or take a few depending on where it held its head). It is believed to have used its incredible height to eat from gingko trees, confers and cycads, among other things.