An unnamed, five-headed dragon subdued by the Buddhist goddess Benzaiten
As a child the prophet Merlin was to be sacrificed to a red dragon and a white dragon, but won his freedom by foreseeing their battle and the victory of the red dragon.
Tiamat and Apsu from Babylonian mythology are sometimes considered dragons
Unnamed dragons (there used to be three: two males and one female but the males killed each other in the first mating season leaving the female alone for millennia) in The Belgariad and The Malloreon series of fantasy novels by David and Leigh Eddings.