In the key of Gb Major, all notes have flats except the “F”. The scale is shown below.
The diatonic chords in Gb Major are shown in the next picture.
Lastly, we have guitar diagrams for the chords in the key. Remember that “Cb” and “B” are actually the same note. The same is true of “Fb” and “E”, as you will notice in the key of Cb Major.