E Chords, Blues Bass
54 qualities on E. The seventh chords are where a blues usually sits; the rest are here for the song that wants one.
Every quality this site draws on the root E, in 10 families. A blues leans hardest on the dominant seventh and its ninth and thirteenth relatives — a chord that would sound unfinished in a pop song is the resting chord here — and the others are for the tune that asks for one.
The bass carries a repeating figure under every bar that moves with each change of chord and tells the rest of the band the change has arrived. It seldom sounds the whole chord: it picks which tones to step through and in what order, and the band hears the harmony from whatever note it lands on at the top of the bar.