Search for Blex

Look at the top five cards of your library. You may put any number of them into your hand and the rest into your graveyard. You lose 3 life for each card you put into your hand this way.

Blex, Vexing Pest

Other Pests, Bats, Insects, Snakes, and Spiders you control get +1/+1.
When Blex, Vexing Pest dies, you gain 4 life.

Blex, Vexing Pest // Search for Blex

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.)

Kelinore Bat

Foundry Screecher

Flying
Foundry Screecher gets +1/+0 as long as you control an artifact.

Dakmor Bat

Duskhunter Bat

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

Blighted Bat

Flying
{1}: Blighted Bat gains haste until end of turn.

Gloomhunter

Bartizan Bats

Flying (This creature can't be blocked except by creatures with flying or reach.)

Abolisher of Bloodlines

Flying
When this creature transforms into Abolisher of Bloodlines, target opponent sacrifices three creatures.

Voldaren Pariah

Flying
Sacrifice three other creatures: Transform Voldaren Pariah.
Madness {B}{B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Voldaren Pariah // Abolisher of Bloodlines

Eyetwitch

Flying
When Eyetwitch 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.)

Ghastly Gloomhunter

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

Bloodhunter Bat

Flying
When Bloodhunter Bat enters the battlefield, target player loses 2 life and you gain 2 life.

Vampire Bats

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

Gurmag Swiftwing

Dirge Bat

Mutate {4}{B}{B} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Flash
Flying
Whenever this creature mutates, destroy target creature or planeswalker an opponent controls.

Grimclaw Bats

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

Sengir Bats

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

Blight Keeper

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

Marrow Bats

Flying
Pay 4 life: Regenerate Marrow Bats.

Stalking Vampire

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

Screeching Bat

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

Screeching Bat // Stalking Vampire

Dementia Bat

Flying
{4}{B}, Sacrifice Dementia Bat: Target player discards two cards.

Malakir Familiar

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