tl;dr: Open Culture has compiled a directory of 1,700 free online courses from universities like Yale, MIT, Harvard, and Oxford, spanning humanities, sciences, languages, law, and the arts. Many are MOOCs from Coursera, edX, and FutureLearn—users can audit them for free, though certificates require paid fees (which generate affiliate commissions for the site). Notable offerings include Yale's Financial Markets with Robert Shiller, MIT's Principles of Microeconomics, Harvard's CopyrightX, and language courses in 40+ languages.