With free electricity and good space, GPU mining can still work for coins like Kaspa or Ravencoin. For a rig, look at motherboards like the ASUS B250 Mining Expert and power supplies like the Corsair HX1200. Check YouTube for tutorials on setting up GPU rigs, and use tools like ASICprofit to find the most profitable coins. Keep it efficient and good luck!
Cheap or even free electricity is the most important key for Mining in general , and who ever has that should be not scared about mining with GPUs.
There are still some Altcoins thats worth it to mine it , or you pointing your miners to some Multipool where you can choose what want in return of it.
Prohashing was one of the best things i have done when i was still in mining , but i already gave up on it as in Germany the electricity costs to much.