Gloom Surgeon

If combat damage would be dealt to Gloom Surgeon, prevent that damage and exile that many cards from the top of your library.

Carrion Crow

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

Necrotic Plague

Enchant creature
Enchanted creature has "At the beginning of your upkeep, sacrifice this creature."
When enchanted creature dies, its controller chooses target creature one of their opponents controls. Return Necrotic Plague from its owner's graveyard to the battlefield attached to that creature.

Blessing of Leeches

Flash
Enchant creature
At the beginning of your upkeep, you lose 1 life.
{0}: Regenerate enchanted creature.

Muck Rats

Virulent Plague

Plaguecrafter

When Plaguecrafter enters, each player sacrifices a creature or planeswalker of their choice. Each player who can't discards a card.

Dakmor Plague

Dakmor Plague deals 3 damage to each creature and each player.

Crow of Dark Tidings

Flying
When this creature enters or dies, mill two cards. (Put the top two cards of your library into your graveyard.)

Crow Storm

Create a 1/2 blue Bird creature token with flying named Storm Crow.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Squelching Leeches

Squelching Leeches's power and toughness are each equal to the number of Swamps you control.

Medicine Bag

{1}, {T}, Discard a card: Regenerate target creature.

Plague Rats

Plague Rats's power and toughness are each equal to the number of creatures named Plague Rats on the battlefield.

Murder of Crows

Flying
Whenever another creature dies, you may draw a card. If you do, discard a card.