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.

Dogged Pursuit

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

Jaddi Offshoot

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

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.

Fog of War

You gain 1 life for each creature on the battlefield. Prevent all combat damage that would be dealt this turn by creatures with power 3 or less.

Grazing Gladehart

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

Essence Warden

Whenever another creature enters, you gain 1 life.

Cauldron Familiar

When Cauldron Familiar enters, each opponent loses 1 life and you gain 1 life.
Sacrifice a Food: Return Cauldron Familiar from your graveyard to the battlefield.

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Environmental Sciences

Search your library for a basic land card, reveal it, put it into your hand, then shuffle. You gain 2 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.

Duskwielder

Boast — {1}: Target opponent loses 1 life and you gain 1 life. (Activate only if this creature attacked this turn and only once each turn.)

Nexus Wardens

Reach
Constellation — Whenever an enchantment you control enters, you gain 2 life.

Weather the Storm

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

Healer of the Glade

When Healer of the Glade enters, you gain 3 life.

Moment of Craving

Target creature gets -2/-2 until end of turn. You gain 2 life.

Jungle Hollow

Jungle Hollow enters tapped.
When Jungle Hollow enters, you gain 1 life.
{T}: Add {B} or {G}.

Diregraf Scavenger

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Diregraf Scavenger enters, exile up to one target card from a graveyard. If a creature card was exiled this way, each opponent loses 2 life and you gain 2 life.

Dark Heart of the Wood

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.