Open Educational Resources (OER) are "teaching, learning and research resources that reside in the public domain or have been released under an intellectual property license that permits their free use and re-purposing by others. OER include full courses, course materials, modules, textbooks, streaming videos, tests, software, and any other tools, materials, or techniques used to support access to knowledge."
The Mason OER Metafinder search tool is a federated, up-to-the-minute search that crawls all of the most recent publications from top OER repositories.
OASIS (Openly Available Sources Integrated Search) searches a range of OER materials from multiple sources, such as textbooks, courses, corresponding materials, interactive simulations, and public domain books and resources. It was developed at SUNY Geneseo.