Many OER found online are free for others to use and adapt. However, before implementing another person's or organization's OER for your class, be aware of any usage restrictions or necessary permissions.
e.g. many OER are published with Creative Commons licenses that detail exactly how the work can be shared or reused.
Attribution Best Practices: View examples of how to properly credit or attribute CC-licensed materials for your own courses.
When in doubt about usage rights, contact the OER creator or rights holder(s) directly.
Have you found or adopted a resource that you would like to see on the subject-specific lists? Let us know.