Single Note Permutations is a step further toward developing a fluent technique for combining pick and fingers. Here you'll find more than 1,400 different exercises based entirely on permutations. You should condition your fingers to respond to the intuitive part of your brain when you are playing, not just to play what they can do by themselves.
If you want to get inspired, be original, and get away from your own clichés, this book is for you. 
Level: beginner to advanced