I have a strong understanding of axiology. Decent grasp on the main figures in philosophy of science. However, I have little knowledge of everything else. Would love to learn about any philosopher(s) that stands out to you.
A good candidate might also be Karl Popper. His philosophy is (one of the many) critical reactions to early 20th century logical positivism. Although his falsificationism didn't fare that well in philosophy of science, his more political later writings on the open society led one of his pupils, who became a billionaire, to found open society foundation and one of the most endowed universities in Eastern/Central Europe, the Central European University.
Mostly topics such as feminism and the morality of military intervention in other nations. The Australian philosopher (sounds strange pairing those two words) Peter Singer, who is still alive, deals quite a bit with utilitarianism in the modern day.