The pathfinder city of Alkenstar I think has some really good analogues for piltover. Its a desert city where magic doesn't work. "Inventor" is the primary profession. Steampunk + fantasy alchemy with a good dash of early gun-smithing wild-west mixed in. You could ignore the wild west bit. There is a system-agnostic source book out there somewhere. I would pull from that personally.
The pathfinder city of Alkenstar I think has some really good analogues for piltover. Its a desert city where magic doesn't work. "Inventor" is the primary profession. Steampunk + fantasy alchemy with a good dash of early gun-smithing wild-west mixed in. You could ignore the wild west bit. There is a system-agnostic source book out there somewhere. I would pull from that personally.