This is the treasure hoard chamber of a young golden dragon in my campaign. It's the lowest level of a much larger Dragon's Lair (pt 2) map that I've shared. In my quest, this chamber was used for a boss battle where the party rescued the young dragon from fiends who had weakened her with a bracelet/band of enervation. The fiends were trying to steal one of her eggs so that their master, a demon of great power, could be "re-born" on the material plane. The boss battle began when they interrupted several cultists and lesser demons attempting to remove an egg form the dragon's belly. The main cultist was someone the party had fought before. After seemingly downing the lead cultist, that character revealed themselves to be a formidable demon posing as a cultist, which was a surprise reveal that increased the tension and made the battle more challenging. Additionally, a portal appeared and some of the fiends began to move the dragon's egg towards it, raising the stakes even more. The party almost defeated all the fiends after the warlock destroyed the band of enervation that had allowed the demons to subdue the dragon and the cleric healed the dragon, but the big bad escaped with an egg after barely surviving the dragon's breath attack.