The forgotten G.
Gangstarr
Marvin Gaye
Bebel Gilberto
Goldie Looking Chain
Gorrilaz
Gorky’s Zygotic Mynci
Grand Puba
Grateful Dead
Al Green
Buddy Guy
The only reason I’d choose G is for Genesis (though using surname sorting, I’d get the bonus of Peter Gabriel), but they lose out to S because I then get Supertramp, Steely Dan and Santana.