Soul Wardenutility$2.76Triggers on any creature entering the battlefield and gains you 1 life each time, making it the closest functional analogue. It is a creature instead of an enchantment, but fills the same lifegain role at the same cost.
Soul's Attendantutility$9.06Very similar to Ajani's Welcome, gaining 1 life whenever any creature enters the battlefield. It is broader than Ajani's Welcome because it counts all creatures, not just yours.
Auriok Championutility$11.22Gains you 1 life whenever a creature enters the battlefield, and also has protection relevant in creature-heavy environments. It is a stronger but more color-intensive version of the same effect.
Authority of the Consulsutility$5.37A white enchantment that repeatedly gains you life when creatures enter, while also slowing opponents' attackers by tapping them. It serves a similar passive lifegain role with added tempo value.
Daxos, Blessed by the Sunutility$1.20Provides repeatable life gain tied to creatures entering or dying, making it a solid close match for incidental lifegain decks. It is a creature-based payoff rather than a pure enchantment trigger.
Martyr of SandsutilityBudget$0.15A cheap white lifegain card that can generate a large amount of life in the right deck, especially with many white cards. It is not the same trigger, but serves a similar life-buffering function.
Resplendent Angelfinisher$8.47A white lifegain payoff that rewards repeated life gain by creating more board presence. It works in the same archetype, though it costs much more and is a payoff rather than a trigger source.
Cleric Classutility$1.69A white enchantment that repeatedly gains life whenever a creature enters under your control at level 1, closely mirroring Ajani's Welcome. It also scales into a stronger long-game enchantment.