In the past week I've been experimenting with textures in my work flow. I must say that it's lots of fun and certainly adds to the creative process. I found this wonderful site on-line that has thousands of high quality textures available for down load. Many of which are free and then for a relatively small yearly fee you have access to their entire library. They also have tutorials that are very interesting. Here's the link. I think you should try it. If you do, I know you'll enjoy it.