Some of my lockdown reading has been Keith Richards' autobiography. I skipped most of the druggy bits but there's some interesting guitar related stuff in it. He talks about discovering open tunings, in particular open G. I take it this is D-G-D-G-B-D? (I'm assuming you can only lower the pitch of strings, not raise them, to avoid breakages.) He also says he didn't use the lowest string, so he took it off and later had special 5-string guitars made for this tuning.
Thinking about it, I wonder if an open G minor tuning would work: lower the B string to Bb. Then you could play minor chords as simple barres, but major chords would also be easy as they'd be a barre with a second finger on the B string. Has anyone tried this? Does it work?
It would also be interesting to try an open D tuning: D-A-D-F#-A-D. Or open D minor, as above but with the F# dropped to F natural.
I think I'm going to have to play around with these myself!