Recs if you like Iphigenie auf Tauris...

Works I would consider german literary classics. "German" in this context means "written in German", not "written by a German author", therefore Swiss, Austrian, and other authors will also be included on this list, provided they wrote their works in German.

all the classics you might (have had to) read in school in Germany

Meet the literature read in German schools or considered to be part of basic literature education. Old and modern.