OASIS - This multidisciplinary source provides access to a variety of types of OER, including books, lesson plans, podcasts, and primary sources, among others.
Teaching Commons - This site divides its content into textbooks, course sites, syllabi, course materials, and lectures across all disciplines.
Smarthistory/Khan Academy - This site features videos, images, and articles written by academics, on art from antiquity until now.
Heilbrunn Timeline of Art History - From the Metropolitan Museum of Art, this site features detailed essays written by curators, accompanied by images of works from the museum's collection.
Art History Teaching Resources - Populated by art history teachers, this site includes classroom and museum activities, lesson plans, book reviews, and more.
Smarthistory Books - Published by the scholars behind Smarthistory/Khan Academy, these volumes feature essays on specific artworks in various categories, from Asian to contemporary to antiquity.
Open Textbook Library - This site features over 700 open textbooks licensed to be freely used, adapted, and distributed; all are reviewed by academics.
edX - This massive open online course (MOOC) founded by Harvard and MIT provides classes in a range of subjects.
Coursera - This site features constantly rotating courses from universities around the world covering virtually every topic, all of which include video lectures, assignments, and discussion forums.