All might
All Might was the number one hero at the beginning of the anime, and his designs have not changed much. The biggest change is that in the original concept art, he looked older. In his new design, he was drawn to be built stronger and to appear younger so he was more appealing to the audience.
Endeavor
Endeavor was the number two hero, and his physical design did not change, and his hero costume did not change either. The only change was in his actual character involvement in the story because he originally was going to be a teacher at UA.
Midnight
Midnight’s original designs had her outfits more risque because her quirk requires her skin to be exposed. She had more belts and skin exposed and even had a muzzle. But, when we look at the manga compared to the anime, they kept her costume the exact same.