Alpha Omega by Bryan and Katie Torwalt
Original Key: Gb (/Db mixo)
Time: 68 4/4

4 chord song

Cb / Gb/Bb / | Ebm / Dbsus / |

Major mode numerals (Gb):
IV I/iii vi Vsus

Bridge:         v-(It feels like a /vii would fit here, but the bass doesn't)
IV (/V) I/iii vi  V (/riff)

Last instrumental riff:
(vi V IV) I -> to vi chord

Common Riff on Vsus: V vi ^I ^ii ^I ("box" riff)

Lydian mode (B):
I V/vii iii IIsus  (vii a minor chord in this mode, not dim)

Mixolydian mode (Db):
bVII IV/vi ii Isus (I think this makes the most sense, it ends on a good
    tonic-sounding I, but the last instrumental riff also hits the I, and
    the tonic is present in Major mode, just as a split chord)