Open-source game development assets
opengameart.org
opengameart.org
http://opengameart.org/content/recolor-all-the-items
Uses the Dawnbringer 16 palette. This is an awesome 16 color palette that can represent a lot of things and looks great.
http://www.pixeljoint.com/forum/forum_posts.asp?TID=12795
There is also a 32 color variation:
If your in the market for low-end art, there are offshore studios that produce decent stuff incredibly cheaply. $15-$25 hr range. Mid to high end stuff is more difficult and expensive to procure for indies since most really good video game artists have full time jobs at the larger studios and not much spare attention for freelance projects.
Ideally as an indie you want to partner with a really good well rounded artist who devotes their full time attention to the project, when that happens you get unstoppable teams like 2d boy and team meat.
Is a matter of look for them.
http://forums.tigsource.com/index.php?topic=8970.0
I thought it would get old but they ended up being more like archetypes than unoriginal assets.
not sure if people are still playing realm of the mad god but that game was fun as hell.
Also, finding good art can be tough. The search function has gotten a lot better in the last couple months though. I suggest browsing relevant collections, so you can take advantage of the work people have already done to find good stuff.
http://opensource.org/docs/definition.php
The "source" for a bitmap image (PNG/BMP etc) can be a vector image (SVG, PostScript etc) or maybe a multi-layer bitmap image (Gimp, Photoshop etc). The "source" in "open source" refers to that the files that were transformed into the files in question are available under a libre license, not what kind of file format or language they are represented in.