Here's what I did to my wife's 15-bar autoharp.
I recut new felts for each bar.I used a circle of fifths approach, plus the relative minor chord for each of 8 major keys.
Works well for folk music.

    Dm   Am Em   Bm   F#m   C#m   G#m                            .
F    C   G    D    A    E    B    F#                  
.