I realized that most of my dirt pedals are in the Tube Screamer family. Low to mid gain, smooth, not a lot of bite. What are some good distortion pedals that have nothing to do with Tube Screamers that I should try? For the record, I have a Rat-clone, a Maxon SD-9, MXR Distortion + and a fuzz or two. Maybe I just need to stack them.