Rozz Dead Heat

Here is an 18V Big Muff version from the 70s.
Original FSB thread and schematic available here.

21st Century Big Muff

Mictester's version of the Big Muff.
You can find the original FSB thread and schematic here.
I've used the updated schematic on page 2.

DeadAstronautFX Space Patrol Fuzz

Deadastronaut's version of the Big Muff.
Original DIY thread and schematic are available here.
There's also another great layout by Mug in the Forum section.

Catalinbread Manx Loaghtan

I know there have been veros around for a while but I wanted to add this project to the main page.
It's basically a Rams Head Muff with an added Baxandall tone control.
You can find original FSB thread and schematic here.
It should easily fit it in 1590B size box.

Crank both treble and bass and you get a classic scooped midrange. Back both off, while turning up the volume knob and your midrange content increases. Park the treble and roll back the bass and the midrange scoop frequency shifts downward so you have complete control over which frequencies you are cutting. Roll the bass below noon and you start to add a bump to your midrange, which is great for running into a hot amp. This tone control style is capable of numerous sounds, making the Manx Loaghtan one of the most versatile pedals of this style.” - See more at: http://tonereport.com/blogs/lifestyle/big-muff-shootout/page/three#sthash.Pt8yzCYp.dpuf

Baxandall tone control

Rams Head Muff

Rams Head Muff

Rams Head Muff

Rams Head Muff

Sekova Big Muff Model 2015

   This is a rare Japanese Big Muff clone made by Shin Ei. It is a clone of a triangle Big Muff, however it has some substantial differences to the triangle Muff layout we have here on the site. The 47n caps in the clipping stages here vs the 1uf caps in the clipping stages of Mark's triangle Muff layout alone should give you a substantially different sound.

   I based this layout on Mark's classic Big Muff template, and included the series polarity protection diode (D1). This diode is not in the original pedal, and you can omit it if you want.

Madbean Pig Butt

Brian's description:
The PigButt is a modded Op-Amp Muff.
It's a nasty little beast, full of saturated distortion; not too edgy nor too smooth.
It provides a wonderfull "wall of fuzz" like the Big Muff but with a different feel and texture.
The PigButt also features a tone bypass switch for even greater distorted output.

Human Gear Animato

A Bass/Guitar distortion pedal made famous by Christopher Wolstenholme of Muse.
For infos on this project check the original threads on DIY and FSB 
(If you build it for bass you should add a blend circuit to improve the sound)

Mojo Hand Colossus Fuzz

Info about the original:

ALL HAIL THE COLOSSUS!!! Unleashed on an unsuspecting public, the Colossus is THE be all end all Russian/Civil War Muff style fuzz. Ridiculously tweakable, insanely versatile, and packed with 10 tons of Colossal Mojo. Rich harmonic drenched chords, sweet singing leads, sludgy stoner goodness, filthy bluesy mcnasties, Pumpkin flavored raunch…you name it, it does it. It features a 3 way toggle for different EQ voicings, as well as a full range “Mids” control to help you cut through the mix in a live setting.

  Edit: Corrected 2 values. the 2.2nF cap in the tonestack (column k/rows f-h) should be 22nF, and the 5.6nF cap (column b/rows h-l) should be 56nF. This should fix some of the issues with the tone and output of the effect that has been reported.