I have been looking to create a Druid that only wildshapes into dinosaurs and prehistoric beasts. This however only gives you four options at level four.

I have 'adapted' some other beast shapes to be dinosaurs.

Pachycephalosaurus = Giant Goat

Compsognsus = Weasel

Ichthyosaurus = Reef Shark

Dyoplosaurus (a smaller anklosaurus) = Boar (but slashing is replaced with bludgeoning)

Therizinosaurus = Giant Hyena (But bite is now a slashing claw attack)

Terror Bird = Axe Beak

Does anyone have any other suggestions?

Check this out.  Beasts of the jungle rot is great too and is even adventurers league legal.