Goethe, whose main works are Young Werther, Faust and Prometheus;
Schiller, whose main works are Robber, Conspiracy and Love, and Valentin;
Poet Heine, whose main works are The Distress of Youth, Lyric Interlude, The Return of the Native and Beihai Collection;
Hesse, whose main works are Under the Wheel, Wolf in the Wilderness and The Game of Glass Ball.
Gunter grass, whose major works are Tin Drum, Tom and Jerry and Year of the Dog.
Thomas mann, whose main works are Magic Mountain and Budenblock Family.
Remarque, whose main works are Quiet on the Western Front.
Hertha Mueller, whose main works are Breathing Swing, Lowland and Man is a Pheasant in the World.
Generally speaking, German literature is ideological, lacking in sense of humor and rigorous in logic. It will not be easy to read, but once it is understood, it will certainly benefit a lot.
The above recommended "All Quiet on the Western Front" and "Tin Drum" are not difficult to read and the language is humorous.