The Devil's Backbone
Before The Shape of Water, Guillermo del Toro released The Devil's Backbone. This film is set during the Spanish Civil War. It's a psychodrama that does not leave anything to the imagination besides the origin of the specter that resembles the orphaned protagonist of the film. Also, del Toro claims that he loosely based the plot of this movie off of the specter that he was visited by as a child. Creepy.
The Descent
In 2006, action movies were all the rage. The Descent didn't get its proper attention until cult film fans picked up on this masochistic, hyper-stylized thriller. Imagine spelunking so deep into a cave system that you and your friends reach hell. That's what happens in this flick.