Here is a list of mythical creatures beginning with this letter and I am constantly gathering information from each continent and continually updating.
Alom-bag-winno-sis (Abenaki)
They were a race of water dwelling dwarves that resided in deep pools, rivers, and lakes in the most turbulation sections and from under the surface rose to overturn canoes to drown their victims. With the added ability to changed size from small to large and lived mostly in communities under the water.
With a magical kettle when grains of maize were introduced produced ample food for the rest of their kind in the area. Being three feet tall with black hair down past the waist were completely naked, and mostly avoided human interaction on land and said to be an omen of death by drowning.