One and a half months after the free-to-play web-based MMO called Glitch was closed due to a small audience, its creators at Tiny Speck have released nearly all of the assets from the game under a Creative Commons licence. Existing under Creative Commons means the items can be used by anyone, shared or adapted, but not used for commercial purposes. Any use of the items must be attributed to Tiny Speck, and any work using the items can only be distributed under Creative Commons too.
The assets are in the game's Encyclopedia, which is full of sprite sheets and the occasional animated GIF for many of the in-game items. Tiny Speck plains to expand this Encyclopedia and leave it online indefinitely, though cautions that can't be a promise since things inevitably change. And some of the features from Glitch's website will be taken down, with plenty of warning, like the forums and mail.
You only have to read some of the comments on the “Official Encyclopedia Asset Licensing thread” or look at how much fans raised for Indiegogo campaigns to preserve the game's art and music to see how much people loved this wacky game. And it's a shame to see it come to an end.