I have already get something from an airdrop which i don't remember when i participated. You guys please write here if you find a proper exchange, also i couldn't find it on cmc
Yobit already traded the bitcoin gold and the price seems nice in my opinion, but remember you are not able to transfer your bitcoin gold until the network of the bitcoin gold will be live and you will able to send your bitcoin gold after there are some miners are helping to run the bitcoin gold network.
But binance seems to be a recommended choice for you to trade the bitcoin gold after the hardfork. You can try to visit the binance blog and see when the exchange site will be traded the token.