For under $500, I like the DH Labs Q-10 signature. It’s a quad cable of silver-plated high purity copper which adds both fullness and detail. In full disclaimer, I do resell DH Labs products, but I do believe they offer the best bang for the buck when not aiming for total endgame cables.
For your budget, also consider Cerious Technologies Graphene Extreme, or if you can find them, Graphene Matrix (which might cost you a bit more on the used market). They are made with ceramic, graphene, etc. They are quite heavy and thick, but they sound incredible at their price point. They certainly deliver more of everything, including fullness and detail.