RAT
Debuting around 1978, the RAT is known for its aggressive, op-amp-based distortion, sitting between fuzz and distortion. Its circuit inspired many modern distortion pedals.
RAT compared to ...
ProCo RAT Family Tree
FZ-1 Fuzz-ToneTone BenderTriangle Big MuffBig Muff PiRATDS-1 DistortionKatzenkönigPugilist DistortionMTG:LA Tube DistortionHammertone DistortionHammertone MetalFull Moon Distortion+ 35 moreMT-2 Metal ZoneDS-1W Waza Craft DistortionMT-2W Metal Zone Waza Craft DistortionDS-2 Turbo DistortionDS-1X DistortionHD300 Heavy DistortionHot Head DistortionUD100 Ultra DistortionDuel Pugilist Distortion