Mortician Beetle

Whenever a player sacrifices a creature, you may put a +1/+1 counter on this creature.

Wriggling Grub

When this creature dies, create two 1/1 black and green Worm creature tokens.

Gluttonous Slug

Menace
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Fumulus, the Infestation

Flying, deathtouch
Whenever a player sacrifices a nontoken creature, create a 1/1 black Insect creature token with flying.
Whenever an Insect, Leech, Slug, or Worm you control attacks, defending player loses 1 life and you gain 1 life.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent of their choice that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

Slimy Dualleech

At the beginning of combat on your turn, target creature you control with power 2 or less gets +1/+0 and gains deathtouch until end of turn.

Village Rites

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Fleshbag Marauder

When this creature enters, each player sacrifices a creature of their choice.

Mole Worms

You may choose not to untap this creature during your untap step.
{T}: Tap target land. It doesn't untap during its controller's untap step for as long as this creature remains tapped.

Insidious Bookworms

When this creature dies, you may pay {1}{B}. If you do, target player discards a card at random.

Innocent Blood

Each player sacrifices a creature of their choice.

Jet Medallion

Black spells you cast cost {1} less to cast.

Endless Cockroaches

When this creature dies, return it to its owner's hand.

Catacomb Slug

Blood Artist

Whenever this creature or another creature dies, target player loses 1 life and you gain 1 life.

Squelching Leeches

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

Skullslither Worm

When this creature enters, each opponent discards a card. For each opponent who can't, put two +1/+1 counters on this creature.

Giant Slug

{5}: At the beginning of your next upkeep, choose a basic land type. This creature gains landwalk of the chosen type until the end of that turn. (It can't be blocked as long as defending player controls a land of that type.)