OER: Open Educational Resources: Big List of Resources

Discipline-Specific OER from Virginia Tech: Find openly licensed textbooks along with supplemental material, interactive simulations, and other resources.

Subject Resources from University of New Hampshire: A collection of resources divided into humanities, social science, and STEM categories.

Discipline-Specific Resources from VC/UHV Library: A collection of the largest, most popular repositories of open educational resources separated by subject.

WeBWorK: An open-source online homework system for math and science courses. WeBWorK is supported by the MAA and the NSF and comes with a National Problem Library (NPL) of over 20,000 homework problems. Problems in the NPL target most lower division undergraduate math courses and some advanced courses. Supported courses include college algebra, discrete mathematics, probability and statistics, single and multivariable calculus, differential equations, linear algebra and complex analysis.

Academic Earth: Find lectures and videos from some of the most respected instructors in the world.

Coursera: Large library of MOOCs, some of which have material freely licensed for re-use.

EdX: Library of college-level courses from a variety of high-profile universities. Some course materials are freely licensed for reuse.

LearningSpace from Open University: All of the learning materials presented on this site are CC licensed, but don't confuse "Learning Spaces" with the full Open University- their licensing/copyrights are different.

OCW Utah: Open education course materials aimed at a high school level.

Miríadax: Ibero-American MOOC platform with complete courses in Spanish for a variety of topics. Some are paid but you can search by price and filter to $0.

Open Course Library: The WA Open Course Library project offers 81 of Washington's most enrolled courses. There are a lot of great readings in these course files. Great community college content

Open Courseware: A free and open collection of material from thousands of MIT courses, covering the entire MIT curriculum.

Saylor.org: Saylor offers full courses online. It can be really helpful to use the reading lists from Saylor to find and organize your courses.

Open Learning Initiative: Complete courses from Carnegie Mellon University

Noba - Psychology Modules: A series of modules in the field of Psychology from Introductory courses to more advanced topics.

OERu: Offers a number of full courses in fields like business, economics, digital literacy, and history from partner universities around the world.

Open Stax: Rice Connexions is providing peer reviewed, quality open textbooks. 

Open Textbook Library: Hundreds of complete, open college-level textbooks. University of Minnesota collection of open textbooks with full reviews.

BC OpenEd a curated collection of open textbooks, many reviewed by British Columbia faculty.

LibreTexts an infinitely large library through which new texts can be developed & shared, and supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. 

Wikibooks: A project of the Wikimedia Foundation, this collection of group written textbooks in a variety of sources follows rules similar to Wikipedia.

Project Gutenberg: Find the full text of classics and public domain works from the first massive ebook creating organization in existence. Nothing fancy here, just files with the full text.

Google Books: Some books presented in this mass conglomeration of scanned books are fully available, most are excerpted.

American Institute of Mathematics: A list of open textbooks in various subdisciplines of Mathematics approved by the AIM editorial board.

FreeBooks4Doctors: Free medical textbooks.

Lyryx Open Textbooks: High-quality open textbooks in the fields of accounting, mathematics, and economics. They also have optional added (paid) resources such as homeworks and quizzes to accompany the open textbooks.

Bloomsbury Academic: A well-respected and long time UK publisher who has released some of their academic titles for open access/open education.

OASIS: A large user friendly OER search engine that allows for users to search by subject or by course material type (e.g. textbooks, simulations, audio).

Mason OER Metafinder (MOM): This search engine from George Mason University is connected to 15 major OER repositories.

Merlot: This repository is one of the biggest and more famous places to find and share teaching resources.

Connexions: Large repository of individual teachers' content, some courses and lots of modular writings about a variety of topics.

OER Commons: This resource seeks to collect and distribute a variety of OER at a variety of levels and subjects.

Quantitative Undergraduate Biology Education and Synthesis (QUBES): This repository contains learning materials, software, data, and models for teaching quantitative skills in undergraduate biology courses. QUBES is developed in part by faculty at the University of Pittsburgh.

Curriki: Open educational materials for K-12.

AMSER: Materials in the Applied Math and Science Educational Repository are free for use and adaptation. Most resources are at the high school and community college levels.

Edsitement!: Learning objects and lessons from the National Endowment for the Humanities. It offers a large collection of peer evaluated websites.

Community of Online Research Assignments: Open resource for faculty and librarians about Research Assignments. A research assignment is anything that requires students to engage with information resources in a critical or reflective way. This most often includes finding, retrieving, analyzing and evaluating, using and integrating, or organizing the information in order to produce new knowledge.

Google Advanced Search (with "Usage Rights" filter): Use the "Usage Rights" filter on Google's Advanced Search (and Advanced Image Search) to find Creative Commons-licensed works.

OpenCulture: This blog formatted repository seeks to bring together free resources on culture and education. The list of movies here is impressive.

Smarthistory: A free resource for the study of art history created by art historians Beth Harris and Steven Zucker. Smarthistory is an independent not-for-profit organization and the official partner to Khan Academy for art history