Books up top, articles down below. Check back regularly for updates (always in chronological order of publication!) ||| Also, if there is no link for a particular book or article, that means I haven’t found a free/public version yet. Please let me know if you come across any! 

BOOKS:

Plato, The Republic (~4th century (380) BCE (BC))
Aristotle, Nicomachean Ethics (~350 BCE (BC))
Epictetus, Discourses (~100 CE (AD))
Augustine of Hippo, Confessions (~397 CE (AD))
Boethius, Consolation of Philosophy (~500 CE (AD))
Thomas Aquinas, Summa Theologiae (1485)
Niccolo Machiavelli, The Prince (1532)
René Descartes, Discourse on the Method (1637)
René Descartes, Meditations on First Philosophy (1641)
Thomas Hobbes, The Leviathan (1642)
Blaise Pascal, Pensées (1670)
Baruch Spinoza, Ethics (1677)
John Locke, Essay Concerning Human Understanding (1690)
John Locke, Second Treatise of Government (1690)
George Berkeley, Treatise Concerning the Principles of Human Knowledge (1710)
David Hume, An Enquiry Concerning Human Understanding (1748)
Jean-Jacques Rousseau, Discourse on the Origin and Basis of Inequality Among Men (1754)
Immanuel Kant, Critique of Pure Reason (1781)
Immanuel Kant, Critique of Practical Reason (1788)
William Paley, Natural Theology (1802)
Arthur Schopenhauer, The World as Will and Representation (1819)
Karl Marx, The Communist Manifesto (1848)
Charles Darwin, On the Origin of Species (1859)
John Stuart Mill, On Liberty (1859)
John Stuart Mill, Utilitarianism (1861)
Friedrich Nietzsche, Thus Spoke Zarathustra (1881)
Friedrich Nietzsche, On the Genealogy of Morals (1887)
Ludwig Wittgenstein, Tractatus Logico-Philosophicus (1921)
Martin Heidegger, Being and Time (1927)
Karl Popper, The Logic of Scientific Discovery (1934)
AJ Ayer, Language, Truth, and Logic (1936)
Albert Camus, The Myth of Sisyphus(1942)
Jean-Paul Sartre, Being and Nothingness (1943)
Jean-Paul Sartre, Existentialism is a Humanism (1946)
Gilbert Ryle, The Concept of Mind (1949)
Hannah Arendt, The Origins of Totalitarianism (1951)
W.V.O. Quine, From a Logical Point of View (1953)
Ludwig Wittgenstein, Philosophical Investigations (1953)
Thomas Kuhn, The Structure of Scientific Revolutions (1962)
Carl Hempel, Aspects of Scientific Explanation (1965)
Peter Berger, The Sacred Canopy (1967)
John Rawls, A Theory of Justice (1971)
Robert Nozick, Anarchy, State, and Utopia (1974)
Peter Unger, Ignorance: A Case for Scepticism (1975)
Imre Lakatos, The Methodology of Scientific Research Programmes (1978)
Richard Rorty, Philosophy and the Mirror of Nature (1979)
Saul Kripke, Naming and Necessity (1980)
Bas C. van Fraassen, The Scientific Image (1980)
Alasdair MacIntyre, After Virtue (1981)
J. L. Mackie, The Miracle of Theism: Arguments for and against the Existence of God (1982)
Jerry Fodor, The Modularity of Mind (1983)
Thomas Nagel, The View from Nowhere (1986)
Joseph Campbell, The Power of Myth (1988)
Kai Nielsen, Why Be Moral? (1989)
William Alston, Perceiving God (1991)
Daniel Dennett, Consciousness Explained (1991)
Karen Armstrong, A History of God(1993)
Kai Nielsen, Ethics without God (1993)
William Lane Craig, Reasonable Faith (1994)
John Searle, The Construction of Social Reality (1995)
David J. Chalmers, The Conscious Mind (1996)
H. Tristam Engelhardt Jr., The Foundations of Bioethics (1996)
Peter Godfrey-Smith, Theory and Reality (2003)

ARTICLES:

Gottlob Frege (1892) ‘On Sense and Reference’
Bertrand Russell (1905) ‘On Denoting’
William Frankena (1939) ‘The Naturalistic Fallacy’
Alfred Tarski (1944) ‘The Semantic Conception of Truth and the Foundations of Semantics’
W.V.O. Quine (1948) ‘On What There Is’
P.F. Strawson (1950) ‘On Referring’
W.V.O. Quine (1951) ‘Two Dogmas of Empiricism’
J.J.C. Smart (1956) ‘Extreme and Restricted Utilitarianism’
Wilfrid Sellars (1956) ‘Empiricism and the Philosophy of Mind’
H.P. Grice (1957) ‘Meaning’
G.E.M. Anscombe (1958) ‘Modern Moral Philosophy’
Edmund Gettier (1963) ‘Is Justified True Belief Knowledge?’
Peter Singer (1972) ‘Famine, Affluence and Morality’
Donald Davidson (1973) ‘On the Very Idea of a Conceptual Scheme’
Thomas Nagel (1974) ‘What is it Like to be a Bat?’
Hilary Putnam (1975) ‘The Meaning of “Meaning”’
James Rachels (1975) ‘Active and Passive Euthanasia’
H.P. Grice (1976) ‘Logic and Conversation’
Ruth B. Marcus (1980) ‘Moral Dilemmas and Consistency’