All of these chords have a ‘dominant’ sound, which means they are somewhere in-between the ‘happy’ major tonality and the darker ‘minor’ mood.
The two different A7 and the A9 chords are chords for jamming for an entire verse or solo section. The A7#9 (or Hendrix chord) and A13 are more colourful and should be added sparingly to give it character.
The E9 and E13 chords are both typical funk chords, used extensively by James Brown’s guitarist Jimmy Nolen. You can switch between the chords by adding your fourth finger on the first string.
Prog rock chords
The F#add9#11 chord has a bright Lydian mode flavour and instantly brings Steve Vai or Joe Satriani to mind.
The Mikael Åkerfeldt-style F#m add9 is somber, but also very colourful – perfect for an Opeth song.
These chords are all major, which means that they have the root, 3rd and 5th intervals at their core. In a few cases we also add the 6th and 9th intervals for colour.
Since all of the chords in these examples are in the key of G we can also add the open third string to create wider intervals between notes.
The last two chords are played with your thumb over the top of the neck to play the root note, leaving your four fingers to create the chord shape. Listen to Every Kingdom by modern British folk artist Ben Howard for a taste of this approach.