Fingers crossed for total conversions. Give me some non-5e rule systems. (Unlikely, I know. Double unlikely to get anything other than maybe Pathfinder, but I can hope)
Or importing new maps and characters, imagine somebody porting the Resident Evil Mansion or Raccoon Police Station with the Resident Evil Characters. Playing Resident Evil 1 with 5e rules would certainly be something. People have already done it with Men of War Assault Squad 2.