Answer: there are many, but mostly artificial values, except in music. In literature, you have Goethe, Schiller, Schelling, Conrad Ferdinand Meyer, de la Rochefoucault (Undine), Rilke, Borchert, etc. mostly from the romantic period. In philosophy: Kant, Nietzsche, Schopenhauer, Hegel, Fichte, etc. mostly from the romantic period, too. In music: Bach, Schuman, Schubert, Wagner, etc. mostly from the barock or romantic periods. There are many scientists or want to be, like Humboldt (XIXth), and little more.
Sometimes, when under German is understood the somewhat larger field of ‘German language territory’, there are many others considered, belonging to Austria, Switzerland or old German speaking territories (Liszt, Hungaria, Kafka, Hungaria, etc. are often ranged under ‘German’ although they aren’t). German speaking populations were alive even in the forlorn countries of Caucase and are still to be found in countries like Serbia, Hungaria, Rumania, Poland, etc.