I use Drop- D tuning quite a bit for both fingerstyle and backup playing. Make a G maj. chord at the third fret and where you would normally barre the 3rd fret in standard, in Drop- D (with the 6th string lowered one step to D):

1. fret the 1st and 2nd string with your index finger at the 3rd fret

2. the 3rd string, 4th fret with your middle finger

3. the fourth string, 5th fret with your ring finger

4. the 6th string, 5th fret with your pinky while muting the 5th string.

Now you have a highly mobile major chord. If you extend your index finger barre, as I do, to include the 3rd string, 3rd fret you can lift your middle finger and you have a movable minor chord.
This works for a lot of tunes and songs in various keys and doesn't require full barres or over the top thumb work to get up the neck.