Because Tomb of Annihilation is set in a jungle and deals with death, green and black for that one.
Storm King's Thunder cries out for blue and gray or white, for sky colors.
Dragon Heist, definitely gold. Maybe purple, since that's a 'royal' color for wealthy folks.
Red and black for Curse of Strahd, because vampire.
Dunno about the others right now. Tales from the Yawning Portal is a particularly tough one.