"Mt. Rushmore", in this blog's context, means the four most iconic or important items from a particular D&D topic. Today's topic is Monsters. The previous topics were Spells and Magic Items.
What would your Mt. Rushmore of D&D Monsters look like? You're only allowed four and for this exercise make the list without consulting any D&D books. After making your list, proceed to comments to see mine.
~Sham, Quixotic Referee