OER can be big or small. They include teaching resources such as lesson plans and curriculum guides; learning resources like textbooks and activity sheets; academic papers and articles; radio programs; policy documents; online courses; museum resources like virtual tours; learning management systems; professional development resources; vocational training materials; corporate training; multimedia resources like videos, animations and podcasts; e-books of all kinds; theories, models, frameworks; applications and tools, any many more. 

OER can be produced by anyone. OER also offer opportunity for people to collaborate in creating and adapting resources across sectors and geographical boundaries. If you can produce a word processing document, or take a photo, then you can create an OER. The image below shows the website for the openly licensed e-textbook produced collaboratively by members of The International Association for Child and Adolescent Psychiatry and Allied Professions (IACAPAP).