Once you've filled your boots with DADGAD or double drop D, why not turn your attention to an open tuning that is very popular for clawhammer acoustic guitar, open Gsus4? It is essentially the same as open G tuning, but with the second string raised by a semitone.
So to tune from standard tuning, drop the first, second and sixth strings down a tone and then raise the second string by a semitone. Molly Tuttle uses this tuning for her track Take the Journey.
1. Bbadd9
It’s a little awkward to fit all three fingers in place here, but the results are worth it.
2. Csus2
This chord sounds great following on from the previous shape.
3. Dm7
This fingering here is easy. Simply place your second and third fingers on the second and third strings at the 5th fret.
4. Bbadd9
This chord use the same fingering as the previous Dm7 chord, but places a Bb note in the bass.
5. Amadd11
The final fingering is easy to play and gives a moody minor tonality to experiment with.