Elevating the rear of the notebook can help or an aluminium stand, this will reduce heat being reflected from the surface back to the MBP. Powered coolers with fans have no practical effect on Mac's. Use Mac's Fan Control to increase the base fan speed to a tolerable level. The stock fan curve ramps up far too slowly for gaming, resultantly the chassis becomes heat soaked making it difficult for the system to cool down. Again, reduce settings, resolution etc.
Another option for static setups is a USB powered fan strategically placed so it blows across the MBP keyboard deck (air flow L-R above & below the keyboard).
Unfortunately, Mac's are not designed with gaming in mind and don't have the internal airflow or cooling required. Much the same as gaming notebooks are not noted for their portability or runtime on battery.
Q-6