Graphicriver.net is part of the larger Envito marketplace. Iíve started making and selling some vector items on there for adobe illustrator. they have photoshop assets and other sister sites have 3d assets.
This AI pattern brush is my best seller on there so far.
Right now I'm making some small profits, with hopes of scaling it to more.
The way it works is you submit the art for review. Then if they accept it, they put a price on it. commissions start off at 50% for exclusive items and go up to 75%. The Author retains the copyright to the art and can continue to sell the file over and over. You can also double dip your art, selling photoshop backgrounds on graphic river and the same art on photodune. I haven't tried that trick yet, though I've been taking photos of metal and wood at the shop.
Anyway, it's worth checking out as a user or seller. I'm TradigitalArt on there by the way.
Here a link to my portfolio on G.R.