Here is my list of herbivorous dinosaurs I would like to see in the game. Most of these have had some representation, or at least mention, in the JP franchise. I did avoid mentioning any sauropods, as I feel they pretty much deserve a list of their own.
10)
Dryosaurus (seen in the first novel and featured in Operation Genesis)
9)
Euoplocephalus (listed as part of the dinosaurs in the park in the first novel)
8)
Othneilosaurus (not mentioned in the franchise so far, but the related, though dubious, genus
Othnielia was featured in the first novel, and much of the material that was associated with that genus has since been reassigned to
Othneilosaurus)
7)
Hadrosaurus (also listed on the park list in the first novel, though like
Euoplocephalus, I don't recall it being actually seen. It was also one of the first North American dinosaurs discovered, the first to be described from more material than a few teeth, and the first dinosaur skeleton in the world to be mounted, so, yeah, it deserves to be in the game.

)
6)
Psittacosaurus (featured in the Universal Studios Park rides)
5)
Prenocephale (like
Othneilosaurus, hasn't itself been mentioned in the franchise to my knowledge, but a relative,
Homalocephale, was featured in Operation Genesis. And like
Dracorex and
Stygimoloch are thought to be juvenile versions of
Pachycephalosaurus,
Homalocephale is thought to be a juvenile form of
Prenocephale, so...
4)
Ouranosaurus (part of Operation Genesis, and a popular request, if I understand correct.
3)
Mononykus (part of Lockwood's collection in his manor in
Fallen Kingdom; might be difficult to implement due to being smaller than the in game
Troodon)
2)
Protoceratops (part of Lockwood's collection in his manor in
Fallen Kingdom)
1)
Plateosaurus (not sure if the animal itself has been featured in the franchise, but by God, WE NEED SOME TRIASSIC DINOS IN THIS GAME

)