Some types of dragons:

Lexicon

A fabulous dragon normally represented as a large winged serpent with a crested head and huge claws.

Amphisbaena

A dragon with heads at each end of its body that can move in two directions.

Hydra

A many-headed serpent, often seen with the body of a dragon. It has a lot of heads.

Wyvern

Very similar to a dragon except it only has two legs (most dragons have four) and two wings in all other aspects it is similar to a dragon. They are known for breathing flame, but some don’t.