These are the open position Dominant 7th Chords. In music a Dominant 7th Chord is a chord that has a Root, a Major third, a Perfect fifth and a Minor seventh. It can be thought of as a major chord with the addition of a minor seventh. Dominant 7th chords tend to have a happy but bluesy sound. Below is a table of the of the chords above with notes that make them.
|Dominant Seventh Chord||Root||Major Third||Perfect Fifth||Minor Seventh|