There are many source of open educational resources, from large repositories to more specialized sites. This page provides an overview of some sources of OERs. Note that some sites also host non-free content, so be sure to check the licensing of specific resources before use. You can also contact your subject librarian for assistance with finding OERs.
See also our Guide to Open Access.
In addition to OER-specific sources, you can also seek appropriate content using more general search interfaces like Google and YouTube. Both of these sites have an advanced search option that allows you to limit your search results to items with particular reuse rights.