Creative Commons Licenses

Popular Sites with CC Licensed Content

• Flickr -- Images from Flickr also appear in Google image search results.
• YouTube -- Do a keyword search > click on "Filters" > select "Creative Commons" under "Features"
• Google Images -- Search by keyword > click on "Tools" > click on "Usage Rights" and select "Creative Commons licenses"
• Wikipedia -- All content is  under the CC BY-SA 3.0 unported license.
• Openverse -- Search and find images and audio files with CC licenses.

Ebook Sites

• Unglue.it -- Freely licensed ebooks; the site also promotes making more ebooks freely available. 
• BCCampus OpenED -- Open textbooks collection.
• Open Textbook Library
• OpenStax -- Textbooks and other teaching and learning materials.

Remember, there are sites that provide public domain content (e.g., Pexels, and some content at government sites like the Library of Congress and Smithsonian Libraries) but public domain content should not be reused with a CC license.