Yeah probably Piccolo Daimao. Freeza, Cell and Boo would've had potential if two weren't just cooked up in some guy's basement and the other one just was born super powerful with a massive army because his dad ruled the universe or something.
I think it'd have been better if AT had left Freeza's backstory a mystery. Giving him a daddy weakened his image as a super
powerful being who ruled the universe.