Not sure what the OP is looking for, but here goes nothing.
Anything and everything can be found at the Stanford Encyclopedia of Philosophy for free. It’s the largest and most used source of ***academic ***philosophy on line.
A very, very short list follows:
For ontology, read “On What There Is” by W.V.O. Quine and “On Denoting” by Bertrand Russell. These two dominate modern discussions on ontology.
For philosophy of language, read Wittgenstein. Then read him again. (
) For current philosophy of language, read Robert Brandom. (Brandom was recently awarded a $1.5 million dollar grant to stop teaching and just “think.” He’s *that *important.)
For metaphysics, read debates between Peter van Inwagen and Peter Unger over “vagueness.”
For philosophy of science, read Hilary Putnam and Daniel Dennett. (Also see Dennett for free will and philosophy of mind).
For philosophy of religion and the ongoing debate over the problem of evil, read Alvin Plantinga and William Rowe. (Plantinga’s Christian: Rowe’s atheistic). Plantinga and Rowe are the two most influential voices left on this issue, and their disagreement couldn’t be starker.
For ethics, read Russ Shafer-Landau and G. E. Moore for moral realism, Gilbert Harman for moral relativism, R. M. Hare for noncognitivism, and J. L. Mackie for moral skepticism. (If you only read two of those, read Mackie and Moore… not because they’re right, but because ALL ongoing debates in ethics are over their work.)
For epistemology, read Harman and Plantinga again.
For political philosophy, read Rawls, Nozick, and Sandel.
That’s my list. Feel free to take shots at it for its many omissions of equally important philosophers.