Before adapting an OER, we have to find one. There are a lot of sources out there which are either open source or freely available (See the FAQ for more information on the difference between these). This page is meant to be a guide to finding and using the best possible sources for your needs.

Use these resources to find OER:

Large Repositories
Connexions: Large repository of individual teachers' content, some courses and lots of modular writings about a variety of topics.
OER Commons: This resource seeks to collect and distribute a variety of OER at a variety of levels and subjects.
The Orange Grove: Florida's collection of open ed sources.
Curriki: Open source materials for K-12.
Open Scout:UK based database of business skills teaching resources. Includes articles, tutorials, video and much more in a variety of languages.
AMSER: Materials in the Applied Math and Science Educational Repository are free for use and adaptation. Most resources are at the high school and community college levels.
Free: The mission of Free is to make the learning resources of the US Government easier to find. There are over 1500 lessons, objects, and tools for teaching from the federal government located here.
Edsitement!: Learning objects and lessons from the National Endowment for the Humanities. It offers a large collection of peer evaluated websites.
Open Education Courses
Open Courseware: An independent search engine that indexes open education classes from places like MIT, Yale and UMass.
LearningSpace from Open University: All of the learning materials presented on this site are CC licensed, but don't confuse "Learning Spaces" with the full Open University- their licensing/copyrights are different.
OCW Utah: Open education course materials aimed at a high school level.
Bridge to Success: Materials, mostly study skills, to support students transitioning to college. Saylor offers full courses online. It can be really helpful to use the reading lists from Saylor to find and organize your courses.
Open Course Library: The WA Open Course Library project offers 81 of Washington's most enrolled courses. There are a lot of great readings in these course files.
OER and Public Domain Books
College Open Textbooks: This effort funded by the Hewlett Foundation, seeks to drive adoption of open textbooks. Many of the books shared on this resources are reviewed.
Open Stax: Rice Connexions is providing peer reviewed, quality open textbooks. There are some amazing textbooks available here, but some are still in production.
Open Academics: University of Minnesota collection of open textbooks with full reviews.
Global Textbook Project: High-level texts hosted or created by the University of Georgia.
Wikibooks: A project of the Wikimedia Foundation, this collection of group written textbooks in a variety of sources follows rules similar to Wikipedia.
Project Gutenberg: Find the full text of classics and public domain works from the first massive ebook creating organization in existence. Nothing fancy here, just files with the full text.
Bloomsbury Academic: Bloomsbury is a well-respected and long time UK publisher who has released some of their academic titles for open access/open education.
Boundless: Boundless works with experts to compile web-based openly available content into the same general arrangment of textbooks. You can actually search the ISBN for your current textbook and see what content Boundless would use to replace it.
Multimedia Resources
Ted: Inspiring thinkers on a range of subjects present big ideas and lectures on a regular basis- completely CC licensed.
Wikimedia Commons: The thinkers behind Wikipedia bring you images, video and music all openly licensed or in the public domain.
CLIP Information Literacy Tutorials: Find great tutorials on information and research competencies.
HippoCampus: HippoCampus, a project of the Monterey Institute of Technology and Education (MITE), is full of high-quality resources in a variety of subjects. It is aimed at high school and college level users.
PhET Science Simulations: These interactive tools from the University of Colorado at Boulder are mostly CC licensed.
Jamendo: Songs by musicians who want to share their music.
Reference Works
Wikipedia: This well-known encyclopedia is completely open source. Adapt the writing here as you see fit, but attribute wisely.
Scholarpedia: MediaWiki brings you this scholarly version of Wikipedia. For the user, it works largely the same way- except that all articles are mediated by proven scholarly experts. *Please note, some articles in this resource are NOT open source.
Images and Artwork
Creative Commons Search: Creative Commons has created this really useful search engine that lets you search for resources that are CC licensed. The image search is the most useful.

Use these resources to find Freely Available/Open Access Resources.

Large Repositories
Merlot: This repository is one of the biggest and more famous places to find and share teaching resources.
Open Culture: This blog formatted repository seeks to bring together free resources on culture and education. The list of movies here is impressive.
Online Courses and Lectures
Academic Earth: Find lectures and videos from some of the most respected instructors in the world.
Stem Cell School: Lessons and quality digital imaging about stem cells and stem cell science.
Texts and Books
Google Books: Some books presented in this mass conglomeration of scanned books are fully available, most are excerpted.
Multimedia Resources
Vimeo: A social network of video producers. This is a great place to look for a wide variety of content- some is completely open for redistribution, some is open access.
Critical Commons: A community of people who seek to promote the use of media in teaching. The materials posted here are mostly presented using Fair Use guidelines.
Journals and Articles
Public Library of Science: An open publisher whose mission is to change the nature of sharing scientific research through open access.
Directory of Open Access Journals: The most comprehensive collection of open access journals in a variety of disciplines. Unfortunately, you can search by journal subject, but not by article subject.
Reference Works
Stanford Encyclopedia of Philosophy: The SEP is 100% copyright protected, but it is completely open access. This resource is pretty high-level but has an impressive editorial process.

Search Openly Available Video