The Mason OER Metafinder helps you find Open Educational Resources. The OER Metafinder performs a simultaneous search across 21 different sources of open educational materials. Because it is a real-time, federated search, it can take a bit longer than searches of pre-indexed, curated content; however, as compensation the results returned are absolutely up-to-the-minute for each search target.
DPLA connects people to the riches held within America’s libraries, archives, museums, and other cultural heritage institutions. All of the materials found through DPLA—photographs, books, maps, news footage, oral histories, personal letters, museum objects, artwork, government documents, and so much more—are free and immediately available in digital format.
OpenStax is a nonprofit educational initiative based whose mission is to give every student the tools they need to be successful in the classroom. They publish high-quality, peer-reviewed, openly licensed college textbooks that are absolutely free online and low cost in print.
SPARC (the Scholarly Publishing and Academic Resources Coalition) works to enable the open sharing of research outputs and educational materials in order to democratize access to knowledge, accelerate discovery, and increase the return on our investment in research and education.
This site has been around for years, and for good reason – it meets the needs of K-12 teachers. In addition to the usual assortment of OER content, teachers will find full lesson plans that are easily incorporated into classrooms.