This is maybe obscure but Earl Scruggs basically invented three finger picking on the banjo. It became one of the defining characteristics of bluegrass music and when most people imagine “banjo music” today, that’s probably what they imagine first. (It’s called “Scruggs Style” and he popularized but who knows who did it first as a lark?)

A recent one is abusing autotune. Autotune was invented to correct singing notes that were slightly off. Cher was apparently first to do this but people started experimenting with unintended settings combinations to make different effects and stuff. T-Pain took that to the extreme and it became a whole trend in pop music.

Plus, like, the entire history of music in New Orleans and the surrounding Mississippi Delta region. So much American (and British) music can trace a direct line to the blues, jazz, early rock and roll, and other genres that begin in the region.