Three dinosaurs and a sea reptile
The dinosaur hub has the two names every kid knows, T. rex and triceratops, plus the armored ankylosaurus. All three lived in the Late Cretaceous. The mosasaurus lived then too, but it was a marine reptile rather than a dinosaur, a distinction older kids enjoy catching.
Birthday invitations and classroom units
Dinosaur clipart is mostly birthday-party material: invitations, banners, cupcake toppers and favor tags, where the soft watercolor style keeps a T. rex friendly rather than scary. In classrooms the four species make a quick compare-and-contrast sheet (plant-eater vs. meat-eater, land vs. sea). For nursery art, pick one species per print and leave plenty of white space.