The game Glitch by Tiny Speck shut down, and now opens up their image repository to the broad masses. Anybody can use their assets for free under the Creative Commons Licence. You can find all the information and download here: http://www.glitchthegame.com/public-domain-game-art/
If you don’t posses Flash CS5 or higher skip this paragraph. So you posses it, right? Else you wouldn’t read any further?! Good. Lady/Sire, you’re one lucky Person. It seems like you can really use all of the animation and their assests, and have the possibility to get all the graphics in a structured way. Just follow the link and read through the description. Sadly, I can’t tell you, how to work with their assests, because I don’t posses a Flash Version.
I took a quick peak inside the assets. This thing is gigantic! There are more then 10.000 graphics inside, and a lot of animations. Heaven on earth? Hm, not really. If you download the flat images, you find yourself in a gigantic folder structure and you will probably have no idea where to start. If you’ve got some time, you can browse through all the files, and I’m pretty sure it will be worth the time. I took a look at some of the graphics. Some are so specific, that you will have no use for them, but you will also find graphics of plants or landscapes, which are really good! Here’s one example I found:
So, if you’re a game developer be sure to check out their assets, it with be worth a look!