Malekko B:assmaster (standard silicon version) - buzzy, nasty, cuts through any mix. Has a great clean blend, which I know a lot of people value, but I often use it with the cleans all the way off.
Devi Ever Cherry Pop - no longer in production, but you may be able to get a similar sound with the War Horse - her Soda Meiser circuit with a tone control. A great, gnarly fuzz that can get more low end than you'd believe.
Devi Ever VFM - Great, synthy, disharmonic octave-up-y fuzz.
McSpunckle Gnomeratron VTF - an absolute beast of a pedal, capable of everything from muff-y to octave insanity. With switchable diodes, switchable octave, switchable tone profiles, a gate control, a gain control (and more) there are more options than you'd ever need, and yes there is a clean blend. The octave up is pretty unique, and has a really cool almost modulated thing going on. Plus, if you don't like so many options, you can get a more streamlined version in the Mini Gnome.
Danelectro French Toast - a clone of the Foxx Tone Machine. The thickest, nastiest thing ever. Yes, tons of low end. Also, switchable cutting octave. Probably not the best build quality, and no LED, but you can get these for as cheap as $35.
Mellowtone Wolf Computer - not often mentioned here, and there is some low-end loss, but good god can this thing go crazy. Everything from gritty OD to full-bore fuzz to crazy space invader 8-bit madness.
Mid-Fi Clari(not) - not just a fuzz pedal, this thing is some kind of crazy mutant slapback delay fuzz... the delay is waayyyyyyyyyyyyyyyyyy crazy, though, and you can get all sorts of whacked out backwards-bagpipe-esque noises from it. Or, if you really want, you can dial the fuzz/delay blend all the way to fuzz and just have it be nasty & rude.
Annnnnnd while it's not the best bass fuzz pedal, I can never get rid of my ProCo Rat. There are just some toanz I just can't get anywhere else.
