Philosophical Investigations (Wittgenstein), A Theory of Justice (Rawls), and The Structure of Scientific Revolutions (Kuhn) have all been pretty influential.

https://en.wikipedia.org/wiki/Naming_and_Necessity

If anything from 1926 onwards is fair game, then tons of work in the foundations of mathematics. And if you're willing to be slightly more more generous with your time-frame: Russel's paradox.