I have an idea to bring the marketplace to life.
Just like in Diablo, it would be nice to have equipment sets which, when worn together with other set pieces, gives special stat bonuses. These set pieces can only be obtained BY CHANCE if you defeat an opponent on certain combat conditions (for example: "Assassin" set pieces have a 3% drop rate when you defeat an enemy within 3 turns. "Sorcerer" set pieces have 3% drop rate when you deliver the finishing blow with a magic attack, etc.) These sets must also be capped at certain quantity.
Then there are ultra rare items that can only crafted using materials from specific melted NFTs.