I Will Wait by Mumford & Sons is in Gb at 130 beats per minute and runs 4:31 across 73 bars. It uses 7 chords — Bbm, Ab, Db, Gb, Absus4, Fm, Dbmaj7. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? I Will Wait guitar melody tab.