The user has lung capacity and/or ability to use the oxygen very effectively enabling them to hold their breath for extended periods of time while staying active. This may also include birdlike lungs that allow the user to keep their lungs constantly filled with fresh air.
While this ability allows one to survive extended periods without breathing, that doesn't mean they don't need air, but they can survive for long periods without it. Sooner or later they are going to have to breathe.
Free-diving is a mundane and learn-able version of this power.
Demon Hunters (Demon Slayer: Kimetsu no Yaiba)
Krillin (Dragon Ball Series)
Saiyans (Dragon Ball Series)
Various Gourmet Hunters/Bishokuya (Toriko)
Roronoa Zoro (One Piece)
Vinsmoke Sanji (One Piece)
Monkey D. Luffy (One Piece)
Mogana Kikaijima (Medaka Box)
Najimi Ajimu (Medaka Box); with Battle Longer (Biological Skill)
Clan Shiyuu (Kingdom)
Morel Mackernasey (Hunter X Hunter)
Dragon Slayers (Fairy Tail)
God Slayers (Fairy Tail)
Cannonbolt (Ben 10 Series)
Humungousaur (Ben 10 Series)
Kickin Kawk (Ben 10: Omniverse)
Breath Boy (Legion of Superheroes)
Pinkamena "Pinkie" Diane Pie (My Little Pony Series)
Cheese Sandwich (My Little Pony: Friendship is Magic)