I have done several pieces of art for openEtG. I am posting the link to the corresponding openEtG forum here so that anyone who wants to use them can feel free to do so (just mention me in the art credits of course).
I think they are all in 128x128 format, but some of them have the larger versions in spoiler beneath. If not, let me know and I can try to dig up the larger version for you since I usually make them at least 300x300 to start and then shrink them down after.
http://etg.dek.im/forum/index.php?topic=78.0