This month's Sketchbook theme is Filth.
As of posting, there are 11 slots available that will close on Wednesday, July 27th.
Form:
https://forms.gle/fJGChCKYv12WRkaL6$5 for a Sketch
$10 for a Colored Sketch
Note: Filth can mean mud, scat, smeg, musk, etc... Basically just has to be dirty.
If you're not sure if an idea qualifies, feel free to ask.