Open G chords are popular with a number of artists, they are especially good for creating a country blues sound. Kieth Richards from the Rolling Stones has used this tuning extensively, in the right hands this tuning can produce some easy to play catchy riffs. (Tip: Sonny Landreth, Keith Richards, and other open-G masters often lower the second string slightly so the major third is in tune with the overtone series. This adjustment dials out the dissonance, and makes those big, one-finger major chords come alive.)

G Minor Pentatonic Scale in Open G tuning for guitar

The notes used in the G “Minor Pentatonic Scale” are;
G (root note),
Bb (flat 3^rd),
C (4^th),
D (5^th) and
F (flat 7^th).
 

Links to songs in Open G

Rolling Stones – Honky Tonk Woman

justinguitar.com/HonkyTonkWoman