This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Zmeu (Romanian folklore)
Though referred by some sources as a dragon, the zmeu is distinct, because it usually has clear animal traits: it is humanoid and has legs, arms, the ability to create and use artifacts such as weapons, and to ride a horse, and has the desire to marry young girls. Some even compare it to a giant (equivalent of an ogre), or a devil, or even a vampire.
In some stories, Zmeu appears in the sky and spits fire, or has the ability to change form. In other stories, it has a magical precious stone on its head that shines like the sun. It likes beautiful young girls, whom it kidnaps, usually for the purpose of marrying them. It is almost always defeated by a daring prince or knight-errant.