Parasaurolophus: Use these in an attack pack of four on the 3rd level. You can easily kill the pachy, hunters, and compys without being heavily damaged. On any other levels, use them for clearing paths and for luring wild dinos near hunter encampments. Their speed makes them good scouts.

Procompsognathus: Not much use for anything but a scout. Never attack anything with them unless you just don't care. I recommend saving their eggs for points instead of hatching them.

Pachycephalosaurus: These guys make excellent attack dogs on anthing small except the velociraptors. They are perfect matches for dilophosaurs.

Dilophosaur: No match for anything but compys and parasaurs. Use them for attacking across barriers to make them worth hatching.

Stegosaur: A stegosaur has no use if you have triceratops. They are slow and stupid. You can use them in earlier levels though. They make a fine match for anything when teamed up with a pair of triceratops.

Triceratops: The Triceratops are extremely powerful and useful. Use them as attack dogs. A pair of them and a stegosaur make a good match with a tank. They also graze very well.

Velociraptor: Singular, they kind of stink. If you pack them together in packs of four or more, they are deadly. You can easily kill a T-rex with a pack of four Velociraptors. I wouldn't suggest using them against tanks.

Tyrannosaurus Rex: By far, the most powerful creature in the game. Use them for destroying anything. A single one is good for destroying a tank or two. They are a bit vulnerable to attacks from packs of Velociraptor, so watch out.