Pound for pound it's Olympic weightlifters by a mile.
When bodyweight is the issue at hand here you could take a elite sprinter, gymnast, high jumper or any athlete from a sport which requires explosive power and who all weigh the same (let's say 180lbs for sake of argument) and have them lift weights from a static position one rep max, like squat, deadlift, bench, etc, and the Olympic weightlifter would win every single time.