I like the basic structure of the Old School Hack monster arrangement. Still, it doesn’t give the new (or experienced) DM a whole lot to work with, or the players much idea what to expect.
Here is a three page bestiary. It was fueled by whim, including various famous monsters. It is not final, but it gives me personally a base to draw from as I consider improvising battles for my player characters.
Fictive Fantasies 