Below are a selection of OER repositories, so that you can easily locate openly-licensed educational materials (syllabi, textbooks, worksheets, and more).
George Mason Metafinder - With the George Mason Metafinder, you can search across multiple OER repositories at once.
OER Commons - Includes an advanced search function allowing users to limit to the specific type of material, license, and other detailed information.
Open Textbook Library - Coordinated through the University of Minnesota, the site offers peer-reviewed, open textbooks.
OpenStax - From Rice University, the site offers a variety of open textbooks in science, math, and the humanities.
MIT Open Textbooks - Open textbooks hosted by MIT, and searchable by department.
MIT Open Courseware - "A web-based publication of virtually all MIT course content." You can also search for syllabi, videos, exams, and download readings.
OER at CUNY - An overview page of the efforts across CUNY, linking to press releases.
OER in CUNY Academic Works - The institutional repository holds many openly-licensed syllabi, textbooks, and other course content created by CUNY faculty.
OER Representatives across CUNY - The list of representaives on each CUNY campus.
SUNY Open Textbooks - A repository of openly-licensed textbooks created at SUNY.
SUNY OER Repository - Allows for searching of materials from SUNY.
Opening Higher Ed - A slideshow by guest speaker Robin DeRosa, for the CUNY/SUNY 2018 OER Showcase.
BASE - "BASE provides more than 240 million documents from more than 8,000 content providers. You can access the full texts of about 60% of the indexed documents for free (Open Access). BASE is operated by Bielefeld University Library, Germany."
CORE - "CORE is the world’s largest aggregator of open access research papers from repositories and journals. It is a not-for-profit service dedicated to the open access mission." (Based in the UK through Open University and Jisc.)
Faculty Guide for Evaluating OER - A checklist from BC OpenCampus to help evaluate open materials.