Traditional English carols, so well written, but not so well arranged. The arrangements I've seen remind me of church hymns, chord after chord. They are good for choirs but not fun for the accompanist. Back when I was playing five church services a week, I particularly looked forward to improvising and sightreading on the spot the impromptu choices of the day. The First Noel is an easy tune, a bit repetitive, and as a result, after arranging different styles, it started going round and round in my head.
Simplicity invites richer chord progressions to match.
I haven't fully exploited this possibility. Instead, I tried to play with counterpoint and different types of accompaniments. My arrangements range from very simple two single voices to more complicated arpeggios. The full scores in PDF format are two pages long each.