Revitalizelife_gain$0.22A very close white life-gain spell that gives you 3 life and can replace itself by drawing a card.
Healing Salvelife_gain$1.44One of the simplest white lifegain effects, with the option to gain 3 life or prevent damage instead.
Good-Fortune Unicornutility$4.02A cheap white permanant that repeatedly supports life gain strategies, though it is not a one-shot spell.
Ajani's Welcomelife_gain$2.25A budget-friendly life-gain enabler that gains life repeatedly as creatures enter the battlefield.
Martyr of Sandslife_gain$0.15A strong white life-gain card that can generate a large burst of life for one mana by revealing white cards.
Healing Handslife_gain$0.13A straightforward sorcery that gains 4 life, making it a near match in role and cost.
Alseid of Life's Bountyprotection$0.22While primarily protection, it also gives a small life gain and fits white decks that care about lifegain triggers.
Rescue Retrieverutility$0.43This is more of a combat-oriented card, but it can help preserve life total and stabilize the board in white decks.