Superboy in "The Super-Dog from Krypton"
*The first appearance of Krypto.*
When a dog in Smallville exhibits super-powers, Superboy finds a rocket ship in which the dog came to Earth. He learns that the dog is Krypto, his own pet from Krypton, that was sent in a rocket by his father but knocked off course by a meteor. Superboy has a good time playing with Krypto, but he causes problems with his tasks and his secret identity. Krypto eventually returns to exploring space, and though glad to be free of trouble, Superboy is sad to see his dog gone again.
Aquaman in "The First Undersea Newspaper"
Green Arrow in "The Defeat of Green Arrow"