G

Don't forget the open chord

No 3 in this one so the tritone doesn't happen but it's an easy shape to grab and you may need one up here.

An option to substitute for a G major perhaps?

In this position the 5 is in the bass

The Minor shape with the 5 in the bass and no tonic. In the 7th position it's a Gm chord

A great voicing for the 3 string this one has the root in the bass and the other two on top to define the chord very clearly. It also forms the basis of a great moveable shape for this voicing.

You won't come accross a minor 6 too often but it's easy to grab on a 3 string, gives us another moveable shape and sounds cool so why not?

Compare this one to the major chord with the 3 up on the 4th fret and you'll see why the 3 is so important.

An important voicing with the root in the bass and the tritone on top. When playing a blues in G you need to wear this one out.

The 6 chord is commonly used in Jazz in place of a major chord. It has a cool sound that shows up in a lot of contemporary music as well. Give it a go.