There are four known Dragonriding mounts in Dragonflight: the Renewed Proto-Drake, Windborne Velocidrake, Highland Drake and Cliffside Wylderdrake. However, a new Dragonriding mount was found during datamining: a Serpent-like mount with wings.
The only hints for its name at the moment are in the achievement to obtain this mount: Winding Slitherdrake.