This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Drakaina (Greek)
In Greek mythology, a drakaina is a female serpent or dragon, sometimes with humanlike features. Python, slain by Apollo, and the earliest representations of Delphyne are shown as simply gigantic serpents, similar to other Greek dragons. However, although the word "drakaina" is literally the feminine form of drakon (Ancient Greek for dragon or serpent), most drakainas had some features of a human woman. Lamia, Campe, Echidna, and many representations of Ceto, Scylla, and Delphyne had the head and torso of a woman.
Medusa is also mentioned as a drakaina while also emphasizing her human aspects; rather than a drakaina alone, it has been argued that she is a woman who has been fused with a dragon. Many of these drakaina had the faces or torsos of human women. They were often described as beautiful and nymph-like, in contrast to their snake-like tails and monstrous behavior. Others were more purely monstrous, but were still coded as female.