@norootcause This may seem niche, but The Modular Synthesizer.
Invented in the 1950s and then ushered into reality by Moog and Buchla in the '60s, then soon by Roland. Used by all your favorite jam bands of the '70s, but very expensive and not reaching nearly the popularity of its contemporary blossoming technology, The Electric Guitar.
All sorts of brands came out with modulars, but it wasn't until the '90s that Dieter Doepfer's "Eurorack" - a "miniature" format for modular - began to infiltrate the scene.
Fast forward to 2025, and Eurorack has become the most popular format, it dominates electronic music with all the brands and DIY being done. There is no serious electronic musician without a modular, and it is probably one of many.