Chords are either major, minor, diminished or augmented. In addition to these chords, there are still chords that could make your songs more interesting.
Let's take C chord as an example.
C major - consist of C E G
C minor - consist of C E flat G
C diminished - consist of C E flat G flat
C augmented - consist of C E G sharp
C9 - C, E, G, D (an additional D note)
Csus4 - C, F, G (an additional F note, but must resolve to C major)
C6 - C, E, G, A (an additional A note)
C7 - C, E, G, B (an additional B note)
An interesting fact is that you could just use the chords given above to play all the white keys from the piano for the whole song. I never tried it before... Maybe I should give it a try and test how it sounds like. I think it will be dull though.
