Meta-Coolers (Dragon Ball Z: The Return of Cooler)
Mister Majestic (Wildstorm/DC Comics)
Namekians (Dragon Ball)
Peyton Westlake (Darkman)
Sonic the Hedgehog (Sonic the Hedgehog)
Spawn (Image Comics)
Stalfos (The Legend of Zelda)
Swampfire (Ben 10)
Vamp (Metal Gear)
Young Xehanort (Kingdom Hearts)
Eternal Atoms users (Bastard!!)
Aoba Takatsu's subordinates (Code: Breaker) possess the ability Cell Stimulation, which causes their cells to grow and regenerate whenever they are attacked, gaining in size and power as long as not all of their cells are destroyed at once.
Kisame Hoshigaki (Naruto) absorbing chakra from his blade, Samehada, to regenerate both damaged tissues and stamina, gaining an upper hand in extended battles.
Marco (One Piece) possesses tremendous durability due to his Blue Flames of Resurrection keep regenerating damage.