DOAB (Directory of Open Access Books)According to the web site, "DOAB is a community-driven discovery service that indexes and provides access to scholarly, peer-reviewed open access books and helps users to find trusted open access book publishers."
HathiTrustAccording to the web site, "The mission of HathiTrust is to contribute to research, scholarship, and the common good by collaboratively collecting, organizing, preserving, communicating, and sharing the record of human knowledge...HathiTrust will be a vital catalyst for emerging forms of research, teaching, and learning that engage the scholarly and cultural record."
Mason OER MetafinderAccording to the web site, it "launches a real-time, simultaneous search across 22 different sources of open educational materials as you hit the Search button."
MERLOT CollectionsAccording to the web site, "The MERLOT collection consists of...discipline-specific learning materials, learning exercises, and Content Builder webpages, together with associated comments, and bookmark collections, all intended to enhance the teaching experience of using a learning material."
OER CommonsAccording to the web site, "OER Commons offers a comprehensive infrastructure for curriculum experts and instructors at all levels to identify high-quality OER and collaborate around their adaptation, evaluation, and use to address the needs of teachers and learners."