The Intel 8080. It didn't revolutionize microprocessors - it created the microprocessor market. "The 4004 and 8008 suggested it, but the 8080 made it real," said Federico Faggin, Intel's lead designer for the 8080 and its predecessor processors, the 4004 and 8008. Prior to the 8080's launch in 1974,...
Tbh 8080 still used to this day although more like in different form (e.g as microcontroller). Was surprised when I opened one of my gaming mouse and found out it use intel 8080 derivative chip as its controller unit.