So, Dinonykos's module is chock-full of dinosaurs and other prehistoric creatures (I think)
...but what are your favorite prehistoric creatures? AD&D has a whole bunch of them (especially dinosaurs), and it would be fun to add these to our mods...
Among the prehistoric animals that were included in 1e AD&D:
Dinosaurs (lots of them! Too many to name...)
Prehistoric mammals (titanothere, baluchitherium, hyenadon, smilodon, mammoth, mastodon, irish deer, cave bear, etc.)
Prehistoric birds (axe beak)
Prehistoric reptiles (elasmosaur, etc.)