Pigtronix Fat Drive

Original info:
"Pigtronix FAT Drive takes a futuristic analog approach to create complex crunch tones using CMOS clipping and a variable low pass filter for tone shaping. Bringing the tone control all the way clockwise takes this filter completely out of the circuit for total transparency and robust low end. Rolling the tone control back smooths out the highs, leaving ample mid-range bloom and bottom end punch.

A Hi / Lo toggle switch brings additional versatility to the FAT Drive’s wide-ranging palette of overdrive tones, altering the gain structure for enhanced crunch and soaring leads. The FAT Drive features true bypass switching and runs fine on standard 9-volt power but ships with an 18-volt adapter for superior headroom, clarity and overall output"
Schematic available here.

Bixonic Expandora

An old circuit that was missing from the main page.

There was a layout by Harald Sabro in the forum section but this one should be easier to build.

I've taken the "Bite" control from Codtone's Expandra.

You can remove it by adding a link between Bite 3 and 2.
I've also added two more layouts, one with "Forbidden" mod and "Edge" pot as suggested by Dino and one for the Expandora II.

Rostex Turbo Metal

I've heard that in 1991 former Lell engineer went on to form a new company called Rostex. At least that's the rumor and i have no other information about the brand or the pedal. You know anything about these (or have a demo clip/video), please do post it in the comment section.

For the layout, in addition to adding series polarity protection and input pulldown, i subbed the output buffer FET to common 2N7000 pinout.

4-knob version:

And the  3-knobbed version:

(Edit 25.5.2018 23:31: fixed a fault with low wiring and added the 3-knob layout
Edit 29.5.2018 20:35: Fixed 3-knob layout that had a misplaced cut on board image)

ProCo Solo

From the source:

The SOLO is the newest member of the Pro Co family of stomp boxes. Although it is housed in the same indestructible and road worthy steel enclosure that has come to be a trademark of Pro Co stomp boxes, the SOLO marks a departure from the RAT series of pedals in more ways than just the new cosmetics. With its enormous range of tones, 3 way selectable “hot, melt, & burn” modes, and highly interactive “scoop” and “tone” controls, the SOLO just might be the most versatile pedal in your arsenal.  

Don’t let the name fool you, the 100% analog SOLO is no one trick pony. It is equally at ease in both lead and rhythm capacities, and with a wide variety of amplifiers and guitars. Capable of going from vibey, chewy, warm low gain tones, to deliciously mean and crushing high gain tones, the Solo still remains remarkably true to the sound that matters most: The sound of you and your guitar. And speaking of staying true to the sound of your guitar, true-bypass switching ensures that when the pedal is off, there is no coloration of your sound.  

 Even in its highest gain settings, the SOLO remains extremely tube-like, articulate and touch sensitive. Complex chords ring out with clarity, leads sustain with ease. Roll back your volume knob and it cleans up, just like a good tube amp would.  The solo uses three pairs of carefully matched (or should we say, carefully mismatched) clipping diodes to produce asymmetrical clipping. The three pairs are accessible via the “hot, melt, burn” slider switch. This has the effect of making the SOLO clip very much like a tube amp going into natural power tube distortion.

You'll notice there's plenty of room to add 3 more clipping options if you want to use a 6 position rotary switch.