Firstly, thanks for this thread!
I have a few suggestions of music box variety which I also requested for in another thread.
Tempest Bay music box
Rifts music box (from all 6 types of rifts)
Brevane and dusken zones music boxes (We have PoW music boxes but none from any of the storm legion zones??)
Hailol Music box (This track only plays in hailol and the hailol dimension)
Dungeon/Raid/warfront music boxes (eg. Greenscale's blight sountrack, black garden soundtrack etc.)
Wedding Music Box (This one only plays in the player wedding area)
Disco theme in draumheim (heard only in bottomtown, the gutter in draumheim)
Guardian and defiant themes (Heard in both sanctum and meridian)