Some famous Expressionist films are The Golem (1915), The Cabinet of Dr. Caligari(1920) and Nosferatu (1922).
The plot of Expressionism films mainly about intellectual topics such as madness, insanity. So, they have a different kind of viewers compared with traditional Hollywood films (with contents about love, action or Chinese kungfu) created for only entertaining purposes.
Expressionism then became an inspiration for other genres especially the film noir in 1940s-1950s. This genre often uses harsh light which creates a highly contrast between light and darkness, black and white. This use of light also appears in some horror movies later such as Alfred Hitchcock films.