Sing A Rainbow by Arthur Hamilton is in Bb at 80 beats per minute and runs 2:35 across 25 bars. It uses 12 chords — F, C7, Bb, Bbm6, Gm7, C13, Fmaj9, F6, and a few more. 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? Sing A Rainbow guitar melody tab.