This may not be under a free, libre or open license.

Liberated Pixel Cup

Collection

Notes

“Liberated Pixel Cup is a two-part competition: make a bunch of awesome free culture licensed artwork, and then program a bunch of free software games that use it.”

http://lpc.opengameart.org/

From OpenGameArt, Creative Commons and Free Software Foundation.

Assets are released under GNU GPL and CC BY-SA.