Reptiles:
* Turtles: All turtles and tortoises lay hard-shelled eggs.
* Lizards: Most lizards lay hard-shelled eggs, but some give birth to live young.
* Snakes: Most snakes lay hard-shelled eggs, but some give birth to live young.
* Crocodiles: Crocodiles lay hard-shelled eggs.
Birds:
* All birds lay hard-shelled eggs.
Other:
* Monotremes: These are mammals that lay eggs, including the echidna and platypus. Their eggs are leathery, not truly hard-shelled, but they are still quite strong.
Important note: Some species within these groups may have evolved different reproductive strategies, so there are exceptions to this list.