- OER Commons is a directory of resources linking to content produced by a wide range of projects and initiatives, offering a single point of access to more than 50,000 high-quality open-education resources.
- Teaching Commons is a directory of open-access textbooks, course materials, lesson plans, multimedia, lectures and other materials from colleges and universities.
- OpenCourseWare is a free and open digital publication of high-quality college and university‐level educational materials.
https://www.oeconsortium.org/faq/what-is-open-courseware/
- Opentax is a directory of free and flexible textbooks and resources.