I’ve been using a variety of media to produce my background textures. I love the effect I can get from high resolution scanned pencil lines. I produced two simple striped textures, one in pencil, and one inverted to look like chalk lines on a blackboard. These are for sale in my image collection on Shutterstock.
I opened an etsy shop to sell my patterns as printable craft papers. It’s a surprisingly time consuming process but I figure once each listing is up there it’s done and can be used repeatedly in the future. Here’s an example.