What are all of the known duck-billed dinosaur species?

"Duckbill" is a vernacular term for Hadrosauridae, a large family of herbivorous dinosaurs, with many different species.

Hadrosauroids

Bactrosaurus

Cedrorestes

Eolambia

Gilmoreosaurus

Levnesovia

Protohadros

Tanius

Hadrosaurids (valid genera)

Amurosaurus

Anasazisaurus

Anatotitan

Angulomastacator

Aralosaurus

Arenysaurus

Barsboldia

Brachylophosaurus

Charonosaurus

Claosaurus

Corythosaurus

Edmonotosaurus

Gryposaurus

Hypacrosaurus

Hypsibema

Jaxartosaurus

Kerberosaurus

Koutalisaurus

Lambeosaurus

Lophorhothon

Maiasaura

Naashoibitosaurus

Nanningosaurus

Nipponosaurus

Olorotitan

Pararhabdodon

Parasaurolophus

Prosaurolophus

Sahaliyania

Saurolophus

Secernosaurus

Shantungosaurus

Telmatosaurus

Tethyshadros

Tsintaosaurus

Velafrons

Wulagasaurus

Zhuchengosaurus

Hadrosaurids (dubious genera)

Arstanosaurus

Cionodon

Diclonius

Hadrosaurus

Hypsibema

Mandschurosaurus

Microhadrosaurus

Orthomerus

Thespesius

Trachodon