A minor 6th chord is created by adding a 6th degree to any minor chord. For example, a Cm6 chord contains the notes C, Eb, G and A (1, b3, 5 and 6). Here are some common open minor 6th chord shapes.
Dm6
Ebm6
Em6
Fm6
F#m6
Gm6
Abm6
Cm6
Dbm6
Am6
Bbm6
Bm6