The different kinds of eggs are:
Egg of Velociraptor-(Smart Carnivore), Tamable
Egg of Brachiosaurus-(Herbivore), Tamable
Egg of Dilophosaur-(Carnivore), Untamable
Egg of Stegosaurus-(Herbivore),bleeballee
Egg of T-Rex-(Carnivore),spawn egg. This particular egg needs to be outside in order to hatch. If you place it underground, in water or in a winter biome it will not hatch. You can see the Type of Egg, Status and Hatching Process when you right click on it with a Dinopedia.