Here are some of the most important or pivotal 19th century German philosophers:

• Georg Wilhelm Friedrich Hegel (1770-1831) was a leading figure of German idealism and one of the most influential philosophers of all time. His work had a profound impact on the development of modern philosophy, theology, and politics.
• Arthur Schopenhauer (1788-1860) was a German philosopher who is best known for his pessimistic philosophy of life. He argued that the world is essentially irrational and that life is full of suffering.
• Karl Marx (1818-1883) was a German philosopher, economist, sociologist, journalist, and revolutionary socialist. His work has had a profound impact on social science, philosophy, and politics. He is best known for his theory of historical materialism, which argues that the material conditions of a society, such as its mode of production, shape its political and social structures.
• Friedrich Nietzsche (1844-1900) was a German philosopher, cultural critic, poet, composer, and philologist whose work has exerted a significant influence on modern intellectual history. His writings cover a wide range of topics, including religion, morality, philosophy of science, and the nature of truth.

These are just a few of the many important 19th century German philosophers. Their work continues to be studied and debated today, and it has had a profound impact on the development of Western thought.