Families:  

Boidae Boas
Pythonidae Pythons
Aniliidae American pipe snakes
Loxocemidae False python
Xenopeltidae Sunbeam snakes
Uropeltidae  Flat-tailed snakes
Cylindrophidae Asian pipe snakes
Anomochelidae
Acrochordidae Elephant's trunk snakes
Leptotyphlopidae Thread snakes
Typhlopidae Blind snakes
Anomalepididae
Tropidophiidae
Colubridae "Typical" snakes
Elapidae Elapids
Atractaspidae
Viperidae Vipers
Laticaudidae Sea kraits
Hydrophiidae Sea snakes
Bolyeriidae Round Island boas
Ungaliophiidae