I recently started an art resources tumblr to share little bits and pieces I've picked up that I think might be useful/ some of my own content I plan to generate myself, you can follow that here helloartresources.tumblr.com/
Even if you don't wanna follow it, I am going to share with you a custom texture pack that I put together this morning with some photoshop magic
download here: adf.ly/ap3Ag
The textures are 300dpi, 21x30cm and very cool indeed!
I'll work on putting together a tutorial on how to use them as well!
Hope that you get some joy/use out of them; no need to credit me if you do use them, but a fav/comment here or there would not go unappreciated!