I am a freelance texture artist. Selling materials i can give bitmaps or a sbsar file if you have the substance plugin.
If you are intrested contact me email@example.com . I can also make proceduraltextures but takes a bit more time.
Here is some of my work.
Here are some For the Whole list go here http://www.kevindt12.portfoliobox.net/untitled-564875tgis83zp
I had some problems with uploading them