system
Given the following post, respond as if you're commenting on Reddit:
human
Lesser-known philosophers/theorists?

I'm curious about some of the philosophers who aren't typically studied in university, or aren't commonly cited in the canon, or have fallen into obscurity. People, perhaps, like Susanne Langer, Hajime Tanabe, Ernest Becker, &amp;c. Cult figures or personal favorites would suffice just as well. 

Thanks in advance.

Edit: Thanks to everyone for your answers - they have helped me get started on my independent research projects (graduating this May!). Many of these philosophers seem promising.
gpt
The first thing that comes to mind for me is Sidgwick. He's hardly unknown, and anyone who studies the history of utilitarianism encounters him pretty quickly, but his work is actually really ahead of its time in many ways: many people call Moore the first contemporary/analytic ethicist, but I'd actually say that it was Sidgwick. He's also a singular influence on such towering contemporary figures as Peter Singer and John Rawls.