How many of you participate at behance.net ? They have some very good graphics listings.
I haven't participated, no. But they are good and are from Adobe. If I am not wrong, you get integration inside Adobe tools as well.
You can buy assets from Behance and then make it useful for your own project. There are people who showcase their work and get hired in return.
That I have seen. ie, some of them getting hired for their showcase. I really hope there is some way to verify that their showcase is genuine.