LEGO's Adventurers line couldn't pass up the chance to include a sub-line that brought its characters to a Lost World, where they had to stop the bad guys from capturing a prehistoric Anachronism Stew. The dinosaur figures were the standardTyrannosaurus rex, Triceratops and Stegosaurus. Many sets came with a "Pteranodon" figure as well, though that particular type of pterosaur may have actually been Geosternbergia.
Released around the same time was a line of easily buildable and reconfigurable dinosaur sets, simply titled Dinosaurs. Each model could be rebuilt into various other prehistoric animals with their spare parts, though these "extra models" were often too inaccurate for comfort.
The later action-oriented ''Dino 2010''/''Dino Attack'' lines. Had mutated prehistoric critters that bore a very faint resemblance to their real-life counterparts, and although both lines were essentially the same, there were slight differences between the European and US releases: in the European Dino 2010, the protagonists merely wanted to contain the beasts; while their US counterparts came equipped with guns instead of capturing equipment.
BIONICLE very nearly averted this trope. Rumors say they originally intended to introduce cybernetic dinosaurs, but that set line got canceled. However the dinosaurs themselves eventually ended up in official canon, and Word of God says that a released model (Skirmix, a rock steed) was actually a close relative to these cyber-dinos.
The Bahrag, queens of Bohrok, look a lot like robotic theropods.
Then, there's LEGO's new venture into prehistoric themes: Dino, which features a similar approach as the above described Adventurers line: people packing serious gear going after dinosaurs. The dino figures themselves are without doubt the best LEGO has ever made, though unfortunately, these are stillJurassic Park-inspired, '80s or '90s-styled reptilian beasts.
As mentioned, quite a few Transformers have dinosaur altmodes. The Dinobots were some of the fans' favorites, and of course Grimlock became a classic nearly on par with Optimus Prime and Megatron.
The entire reason they exist in the first place in Generation 1 was because Optimus thought robot dinosaurs might be useful.
Megatron himself got a dinosaur alt-mode in Beast Wars.
In the video game Transformers: War for Cybertron, Trypticon still has his Tyrannosaurus body design despite the game being set at the beginning of The Great War, millions of years before the Transformers knew about Earth and dinosaurs. Truly the awesomeness of dinosaurs transcends space and time.
Fall of Cybertron has the Dinobots making an appearance with their dino-modes.
This is an in-universe example: Shockwave turned Grimlock and his team into the Dinobots because he thought he could make the ultimate warriors combining their already formidable combat capabilities with aspects of the large organic creatures he had come across when studying Earth for viable sources of energy. Basically, Shockwave thought dinosaurs were cool, and so decided to make robot dinosaurs.
In the early series (when they didn't bother making too much sense), Grimlock once mentioned that any Transformer with a dinosaur altmode—Dinobots, Trypticon, and even Sky Lynx, who turns into some kind of dragon—emits "dinosaur transform static" because of their "dinosaur electrons", which those with the right equipment can track.