There are many listings of OER online, often grouped by discipline. Here you can find selected listings of OER resources, as well as links to more extensive listings elsewhere.
One of the advantages of OER is they allow individuals to use and build on previously accomplished work without needing to reinvent the wheel. Here are links to other guides and listings with numerous OER sources for diverse topics.
Open source textbooks that are written by professional content developers who are experts in their fields and undergo a rigorous peer review process. All textbooks meet standard scope and sequence requirements.
The Open Textbook Library provides a growing catalog of free, peer-reviewed, and openly-licensed textbooks. The Open Textbook Library is supported by the Center for Open Education and the Open Textbook Network.
MERLOT is a curated collection of free and open online teaching, learning, and faculty development services contributed and used by an international education community. The MERLOT Collection is made up of over 40,000 materials in 19 different material type categories.
Open SUNY Textbooks is an open access textbook publishing initiative established by State University of New York libraries and supported by SUNY Innovative Instruction Technology Grants. This pilot initiative publishes high-quality, cost-effective course resources by engaging faculty as authors and peer-reviewers, and libraries as publishing service and infrastructure.
BCcampus was asked to create a collection of open textbooks aligned with the top 40 highest-enrolled subject areas in the province. A second phase was announced in the spring of 2014 to add 20 textbooks targeting trades and skills training. Our open textbooks are openly licensed using a Creative Commons license, and are offered in various e-book formats free of charge, or print on demand books available at cost.
OER Commons helps educators, students, and lifelong learners avoid time-consuming searches and find exactly the right materials. With a single point of access from which they can search, browse, and evaluate resources in OER Commons’ growing collection of over 50,000 high-quality OER everyone can more efficiently find what they need.
Open textbooks, syllabi, and supporting materials created under Affordable Learning Georgia OER grants. Materials are licensed under various Creative Commons licenses.
The OER Commons is an online referatory with links to a wide range of openly-licensed resources including textbooks, labs, assignments, modules, and syllabi. There is a powerful advanced search option that allows instructors and students to identify resources appropriate to their discipline, purpose, and audience education level.
From the "About" page:
The Josquin Research Project (JRP) changes what it means to engage with Renaissance music. Our open-access website not only hosts an ever-growing collection of complete scores, but for the first time makes the music fully searchable: in a few clicks you can identify every instance of a given melodic and/or rhythmic pattern.