C4D pack:
Heres a collection of my favorite C4Ds. There are only 31, but why would you need more^^.
Most of them are wallpapers/large arts, not pngs, if you don't know how to use them here is how i use them in sigs:
Place the c4d where you want it,
Select-> Color Range, select the color of the part of the c4d you want to use,
set the Fuzziness to about 200 (vary to get different outcomes),
Select-> Select inverse, hit delete
Additionally you can set it to screen/lighten.
Most of them are from Deviantart, i only downloaded them, i didn't make them.