Ontology is the field of metaphysics about what exists. Ethics - philosophical reasoning about principles of right conduct, the nature of justice, virtue, and so on. Aesthetics - philosophy of art and beauty. Logic - the field of philosophy concerned with principles of correct reasoning. Philosophy of science asks questions about what it means to do science, the justification for scientific method, and so on.
Philosophy of law applies philosophical reasoning techniques to a study of legal systems.
Philosophy of history is concerned with principles of justification in historical narratives. Obviously, some of these fields overlap. According to Plato, the unexamined life is not worth living. According to Aristotle, the contemplative life is the happy life. Neither of these mean that you must get a graduate degree and become a professor, although that's definitely something to consider.