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.

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.

Overgrown Arch

Defender
{T}: You gain 1 life.
{2}, Sacrifice Overgrown Arch: Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Forest

Mage Hunters' Onslaught

Destroy target creature or planeswalker.
Whenever a creature blocks this turn, its controller loses 1 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.

Witherbloom Pledgemage

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

Honor Troll

Vigilance
If you would gain life, you gain that much life plus 1 instead.
Honor Troll gets +2/+1 as long as you have 25 or more life.

Brackish Trudge

Brackish Trudge enters tapped.
{1}{B}: Return Brackish Trudge from your graveyard to your hand. Activate only if you gained life this turn.

Professor of Zoomancy

When Professor of Zoomancy enters, create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."

Hunt for Specimens

Create a 1/1 black and green Pest creature token with "When this creature dies, you gain 1 life."
Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Necrotic Fumes

As an additional cost to cast this spell, exile a creature you control.
Exile target creature or planeswalker.

Witherbloom Campus

Witherbloom Campus enters tapped.
{T}: Add {B} or {G}.
{4}, {T}: Scry 1.

Witherbloom Apprentice

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

Introduction to Annihilation

Exile target nonland permanent. Its controller draws a card.

Mage Duel

This spell costs {2} less to cast if you've cast another instant or sorcery spell this turn.
Target creature you control gets +1/+2 until end of turn. Then it fights target creature you don't control. (Each deals damage equal to its power to the other.)

Pest Summoning

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

Mortality Spear

This spell costs {2} less to cast if you gained life this turn.
Destroy target nonland permanent.

Devouring Tendrils

Target creature you control deals damage equal to its power to target creature or planeswalker you don't control. When the permanent you don't control dies this turn, you gain 2 life.

Master Symmetrist

Reach
Whenever a creature you control with power equal to its toughness attacks, it gains trample until end of turn.

Swamp

Leech Fanatic

During your turn, Leech Fanatic has lifelink.

Fortifying Draught

You gain 2 life. Target creature gets +X/+X until end of turn, where X is the amount of life you gained this turn.

Lash of Malice

Target creature gets +2/-2 until end of turn.

Flunk

Target creature gets -X/-X until end of turn, where X is 7 minus the number of cards in that creature's controller's hand.

Bookwurm

Trample
When Bookwurm enters, you gain 3 life and draw a card.
{2}{G}: Put Bookwurm from your graveyard into your library third from the top.