I've a folder full of unused designs, some of which I don't plan on using. For this reason I'm trading or reselling them.
The further down the folder it is, the harder the design is to get.
They can be found here: http://sta.sh/219k0s8fjepd
For trading, I'm interested mostly in red skinned demons, especially in a fantasy/medieval setting. I also have a more detailed list of stuff I like here.