A keyword ability that means damage dealt by this creature also causes you to gain that much life. A 3/3 with lifelink attacking and dealing damage gains you 3 life. Lifelink is strong because it makes races very hard for aggro decks to win.
Popular Cards with Lifelink
Danitha Capashen, Paragon
Serra Ascendant
Archon of Sun's GraceWestvale Abbey // Ormendahl, Profane Prince
Archangel of Thune
Murderous Rider // Swift End
Nighthawk Scavenger
Rhox Faithmender
Dragonlord Dromoka
Exalted Sunborn
Lurrus of the Dream-Den
Valkyrie HarbingerShowing 12 of 141 cards with Lifelink