Terms to use in your searches:

• Open Educational Resources
• OER
• Creative Commons License
• CC-BY or any of the other CC license options
• Open Video
• Open Education Pedagogy

From Creative Commons:

Searching for open content is an important function enabled by our approach.

• pictures at Flickr
• albums at Jamendo
• use FigShare for datasets and other research outputs. (Filters by type of license assigned are available for each search)
• The Wikimedia Commons (a core user of our licenses)