Foundry Screecher

Flying
This creature gets +1/+0 as long as you control an artifact.

Bogwater Lumaret

Whenever this creature or another creature you control enters, you gain 1 life.

Blight Keeper

Flying
{7}{B}, {T}, Sacrifice this creature: Target opponent loses 4 life and you gain 4 life.

Gurmag Swiftwing

Grimclaw Bats

Flying
{B}, Pay 1 life: This creature gets +1/+1 until end of turn.

Gloomhunter

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Dakmor Bat

Courier Bat

Flying
When this creature enters, if you gained life this turn, return up to one target creature card from your graveyard to your hand.

Atomize

Destroy target nonland permanent. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Stalking Vampire

At the beginning of your upkeep, you may pay {2}{B}{B}. If you do, transform this creature.

Screeching Bat

Flying
At the beginning of your upkeep, you may pay {2}{B}{B}. If you do, transform this creature.

Screeching Bat // Stalking Vampire

Deep-Cavern Bat

Flying, lifelink
When this creature enters, look at target opponent's hand. You may exile a nonland card from it until this creature leaves the battlefield.

Blighted Bat

Flying
{1}: This creature gains haste until end of turn.

Starscape Cleric

Offspring {2}{B} (You may pay an additional {2}{B} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Flying
This creature can't block.
Whenever you gain life, each opponent loses 1 life.

Pest Rescuer

At the beginning of each upkeep, if you don't control a Pest creature token, create a 1/1 black and green Pest creature token with "When this token dies, you gain 1 life."
If you would gain life, you gain that much life plus 1 instead.

Pest Infestation

Destroy up to X target artifacts and/or enchantments. Create twice X 1/1 black and green Pest creature tokens with "When this token dies, you gain 1 life."

Stirge

Flying
This creature can't block.
Blood Drain — {1}{B}, Pay 1 life, Sacrifice this creature: Draw a card.

Beledros Witherbloom

Flying
At the beginning of each upkeep, create a 1/1 black and green Pest creature token with "When this token dies, you gain 1 life."
Pay 10 life: Untap all lands you control. Activate only once each turn.

Ghastly Gloomhunter

Kicker {3}{B} (You may pay an additional {3}{B} as you cast this spell.)
Flying, lifelink
If this creature was kicked, it enters with two +1/+1 counters on it.

Eyetwitch

Flying
When this creature dies, 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

Starlit Soothsayer

Flying
At the beginning of your end step, if you gained or lost life this turn, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Vampire Bats

Flying (This creature can't be blocked except by creatures with flying or reach.)
{B}: This creature gets +1/+0 until end of turn. Activate no more than twice each turn.

Malakir Familiar

Flying, deathtouch
Whenever you gain life, this creature gets +1/+1 until end of turn.

Swamp

Sengir Bats

Flying
Whenever a creature dealt damage by this creature this turn dies, put a +1/+1 counter on this creature.

Arachnogenesis

Create X 1/2 green Spider creature tokens with reach, where X is the number of creatures attacking you. Prevent all combat damage that would be dealt this turn by non-Spider creatures.

Duskhunter Bat

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Flying

Moonstone Harbinger

Flying, deathtouch
Whenever you gain or lose life during your turn, Bats you control get +1/+0 and gain deathtouch until end of turn. This ability triggers only once each turn.

Blech, Loafing Pest

Whenever you gain life, put a +1/+1 counter on each Pest, Bat, Insect, Snake, and Spider you control.

Moonstone Eulogist

Flying
Whenever a creature an opponent controls dies, you create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")
Whenever you sacrifice an artifact, put a +1/+1 counter on this creature and you gain 1 life.

Pest Mascot

Trample
Whenever you gain life, put a +1/+1 counter on this creature.

Darkstar Augur

Offspring {B} (You may pay an additional {B} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Flying
At the beginning of your upkeep, reveal the top card of your library and put that card into your hand. You lose life equal to its mana value.

Kelinore Bat

Teacher's Pest

Menace (This creature can't be blocked except by two or more creatures.)
Whenever this creature attacks, you gain 1 life.
{B}{G}: Return this card from your graveyard to the battlefield tapped.

Wolfbat

Flying
Whenever you draw your second card each turn, you may pay {B}. If you do, return this card from your graveyard to the battlefield with a finality counter on it. (If a creature with a finality counter on it would die, exile it instead.)

Basilica Screecher

Flying
Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)