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!
Kaspa coin has been mined on asics for a long time now.
Used AMD RX 570 and RX 580 can be a good solution at 30-40 dollars a piece for Ravencoin mining, but it needs to buy a lot of graphics cards. 100 video cards bring a profit of 10 dollars per day.