Electro Harmonix

Logotype uses Skjald.

Standard Big Muff

Uses ITC Pioneer for the "Big Muff" text.

Ram's Head

"Big Muff" set in Arnold Boecklin. Knob legends use Devinne Ornamental

Misc

• Pitch Fork is set in Friz Quadrata

Earthquaker Devices

Logo set in Acadian Scriptorium. Most pedals use Futura Condensed or another condensed geometric work-alike for legends.

Fulltone OCD

"OCD" set in Balloon. Logotype set in Las Vegas Fabulous

Bogner La Grange

La Grange set in Arnold Boecklin

Fuzz Face

Fuzz Face is set in Staccato

TC Electronic

Logotype set in Kabel Black

Wampler

Some variation/combination of: Kabel Black, Marvin Face, Marvin Visions, and Cadet. It is probably just only one of these but I haven't bothered to nail it down. Morley also uses one of these.

MXR

MXR uses Eurostile for most things. The "Script" version of the Phase 90 uses Medusa.

Tube Screamer

I couldn't nail an exact one for this, which was really surprising to me.

Similar to Gas Pipe Gothics

Some similar:

More emblematic of the category and less similar to Tube Screamer: Poster Gothic, Refrigerator, Tungsten, Compacta

Proco Rat

Everything set in Eurostile

Boss

Boss's logo is either custom drawn or uses proprietary fonts. These are some that are similar, with varying degrees of closeness.

(checkmate used by Yamaha on their pedals)

Digitech

Digitech's logo is set in Zekton Black

Keeley

• Compressor Plus uses Cabarga's "Raceway" or one of the numerous copies