Riveteers Overlook

When Riveteers Overlook enters, sacrifice it. When you do, search your library for a basic Swamp, Mountain, or Forest card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Social Climber

Alliance — Whenever another creature you control enters, you gain 1 life.

Radiant Fountain

When Radiant Fountain enters, you gain 2 life.
{T}: Add {C}.

Lampad of Death's Vigil

{1}, Sacrifice a creature: Each opponent loses 1 life and you gain 1 life.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Essence Warden

Whenever another creature enters, you gain 1 life.

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Read the Bones

Scry 2, then draw two cards. You lose 2 life. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Pest Summoning

Create two 1/1 black and green Pest creature tokens with "When this creature dies, you gain 1 life."

Gingerbread Cabin

({T}: Add {G}.)
Gingerbread Cabin enters tapped unless you control three or more other Forests.
When Gingerbread Cabin enters untapped, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Reckoner's Bargain

As an additional cost to cast this spell, sacrifice an artifact or creature.
You gain life equal to the sacrificed permanent's mana value. Draw two cards.

Epicure of Blood

Whenever you gain life, each opponent loses 1 life.

Cast Down

Trespasser's Curse

Enchant player
Whenever a creature enchanted player controls enters, that player loses 1 life and you gain 1 life.

Bushmeat Poacher

{1}, {T}, Sacrifice another creature: You gain life equal to the sacrificed creature's toughness. Draw a card.

Vault Skirge

({B/P} can be paid with either {B} or 2 life.)
Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Grazing Gladehart

Landfall — Whenever a land you control enters, you may gain 2 life.

Infuse with Vitality

Until end of turn, target creature gains deathtouch and "When this creature dies, return it to the battlefield tapped under its owner's control."
You gain 2 life.

Jungle Hollow

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {G}.

Respite

Prevent all combat damage that would be dealt this turn. You gain 1 life for each attacking creature.

Bequeathal

Enchant creature
When enchanted creature dies, you draw two cards.

Kazandu Nectarpot

Landfall — Whenever a land you control enters, you gain 1 life.

Urborg Repossession

Kicker {1}{G} (You may pay an additional {1}{G} as you cast this spell.)
Return target creature card from your graveyard to your hand. You gain 2 life. If this spell was kicked, return another target permanent card from your graveyard to your hand.

Dogged Pursuit

At the beginning of your end step, each opponent loses 1 life and you gain 1 life.

Blood Researcher

Menace (This creature can't be blocked except by two or more creatures.)
Whenever you gain life, put a +1/+1 counter on Blood Researcher.

Crypt Incursion

Exile all creature cards from target player's graveyard. You gain 3 life for each card exiled this way.

Vampire Neonate

{2}, {T}: Each opponent loses 1 life and you gain 1 life.

Sign in Blood

Target player draws two cards and loses 2 life.

Command Tower

Creeping Bloodsucker

At the beginning of your upkeep, Creeping Bloodsucker deals 1 damage to each opponent. You gain life equal to the damage dealt this way.

Serrated Scorpion

When Serrated Scorpion dies, it deals 2 damage to each opponent and you gain 2 life.

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Dina, Soul Steeper

Whenever you gain life, each opponent loses 1 life.
{1}, Sacrifice another creature: Dina, Soul Steeper gets +X/+0 until end of turn, where X is the sacrificed creature's power.

Glimmerpost

When Glimmerpost enters, you gain 1 life for each Locus on the battlefield.
{T}: Add {C}.

Marauding Blight-Priest

Natural End

Destroy target artifact or enchantment. You gain 3 life.

Weather the Storm

You gain 3 life.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Ill-Gotten Inheritance

At the beginning of your upkeep, Ill-Gotten Inheritance deals 1 damage to each opponent and you gain 1 life.
{5}{B}, Sacrifice Ill-Gotten Inheritance: It deals 4 damage to target opponent and you gain 4 life.

Falkenrath Noble

Flying
Whenever Falkenrath Noble or another creature dies, target player loses 1 life and you gain 1 life.

Appetite for the Unnatural

Destroy target artifact or enchantment. You gain 2 life.

Witherbloom Pledgemage

Magecraft — Whenever you cast or copy an instant or sorcery spell, you gain 1 life.

Pulse of Murasa

Return target creature or land card from a graveyard to its owner's hand. You gain 6 life.

Jaddi Offshoot

Defender
Landfall — Whenever a land you control enters, you gain 1 life.

Pristine Talisman

Tamiyo's Safekeeping

Target permanent you control gains hexproof and indestructible until end of turn. You gain 2 life. (A permanent with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)