Frog

Frogs were amphibious creatures native to Earth.

Earth frogs
When the Axons offered axonite to the people of Earth, they used it to make a frog grow in size, demonstrating how it could be used to solve world hunger. (DW: The Claws of Axos)

Other frogs
On Monarch's ship, frogs were used for their poison by the Monarch. The poison had the power to shrink living people. (DW: Four to Doomsday)

Josiah W. Dogbolter was half-frog, half-man. (DWM: The Moderator)

On an unnamed planet, the First Doctor, John and Gillian met a race of hat-wearing talking frog people and helped them catch a shark that was trying to eat them. The frog people helped them search for the the TARDIS when it disappeared. (TVC: Shark Bait)