The F minor sixth chord is a 4-note chord consisting of the notes F, Ab, C and D.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Fm6.
Chords that are a superset of Fm6. The chords include more notes but always F, Ab, C and D.
Chords that are a subset of Fm6. These contain less notes but all of them are included in Fm6.
In case you prefer a non-interactive variant of the chord chart, we've embedded a PNG image below that shows the notes for the the Fm6 chord. Feel free to save or share the image as needed.