The Amazing 7th Chords: Seven Kinds Of 7th Chords (Video)
Perhaps the most useful kind of chord is the 7th chord, partly because there are so many variations of 7ths. Far and away the most-used 7th chord is the dominant 7th, notated as F7, Bb7, D7, etc. But there are also at least 6 other types of 7th chords, including maj7, dim7, aug7, m7, etc. Watch this short video and you’ll get the idea: