Open Educational Resources (OER) are freely accessible, openly licensed text, media, and other digital assets that are useful for teaching, learning, and assessing as well as for research purposes.
TED-Ed is TED’s youth and education initiative. TED-Ed’s mission is to spark and celebrate the ideas of teachers and students around the world.
Open Library is an online project intended to create "one web page for every book ever published". Open Library is a project of the Internet Archive, and it provides online digital copies in multiple formats, created from images of much public domain, out-of-print, and in-print books.
The Open Textbook Library is a growing collection of electronic textbooks covering many academic subject areas, including Business, Mathematics, Science, Humanities and Foreign Languages, and the Social Sciences. The purpose of the Open Textbook Library is to provide free access to textbooks, to reduce student expenditures. All textbooks are complete, have open copyright licenses, and are freely available to faculty and students. Many of the textbooks have been reviewed by faculty from other institutions of higher education.