I might suggest the Wren & Cuff Pickle Pie B is worth a look. Doesn't seem to be as popular on Talkbass as the TFR and other W&C muff-based offerings, but it has plenty of thump plus a clean blend that is designed to avoid the "bees in the background" effect that plagues many high gain pedals with blend knobs. I'm haven't had much time to work with it, but the left side of the Saturation knob in conjunction with the blend yields some great grainy medium-gain fuzz tones that retain the bass and the character of the instrument better than some other muffs I've tried.