I recently got a Zyvex Mastotron to use with my old school Boss Oc2. It has a lot of control over the fuzz tones it generates, and I like the over all tone. I have some other pedals that I’ve been using for fuzz tones: Tech21 Red ripper Boss Metal Zone with two caps removed Joyo Ultimate Drive Ibanez Phathed The Mastotron seems to have the most extreme fuzz and the most control over the sound. I also got a cheap Donner harmonic square pedal. It does various intervals including octave up or down and also can be a chorus pedal. The jury is still out on this pedal, but it works, and the tracking is very good. I also have an Akai Unibass for octave up sounds. It does a good job of that and can do 5ths as well. I don’t like the built in distortion very much, and the form factor is a bit large though.