I seem to have been misinterpreted. A bunch of mythological creatures is not a well defined series. A bunch of half animal creatures would be the multielement equivalent of the original idea. Banshee, Sphinx, Colossus and Shade are not creatures of the same vein as Mermaid and Naga. I would suggest focusing on the animal part and making names up if necessary.
So far animals I think would fit this series well: Fish (obviously), Spider, Snake, Birds, Horse.