Rotfeaster Maggot

When Rotfeaster Maggot enters, exile target creature card from a graveyard. You gain life equal to that card's toughness.

Mortician Beetle

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

Brood of Cockroaches

When Brood of Cockroaches is put into your graveyard from the battlefield, at the beginning of the next end step, you lose 1 life and return Brood of Cockroaches to your hand.

Stirge

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

Broodhatch Nantuko

Whenever Broodhatch Nantuko is dealt damage, you may create that many 1/1 green Insect creature tokens.
Morph {2}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Twigwalker

{1}{G}, Sacrifice Twigwalker: Two target creatures each get +2/+2 until end of turn.

Vampiric Rites

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.

Marker Beetles

When Marker Beetles dies, target creature gets +1/+1 until end of turn.
{2}, Sacrifice Marker Beetles: Draw a card.

Iridescent Hornbeetle

At the beginning of your end step, create a 1/1 green Insect creature token for each +1/+1 counter you've put on creatures under your control this turn.

Dark Privilege

Enchant creature
Enchanted creature gets +1/+1.
Sacrifice a creature: Regenerate enchanted creature.

Swarm of Bloodflies

Flying
Swarm of Bloodflies enters with two +1/+1 counters on it.
Whenever another creature dies, put a +1/+1 counter on Swarm of Bloodflies.

Ironshell Beetle

When Ironshell Beetle enters, put a +1/+1 counter on target creature.

Mazirek, Kraul Death Priest

Flying
Whenever a player sacrifices another permanent, put a +1/+1 counter on each creature you control.

Giant Caterpillar

{G}, Sacrifice Giant Caterpillar: Create a 1/1 green Insect creature token with flying named Butterfly at the beginning of the next end step.

It of the Horrid Swarm

Emerge {6}{G} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, create two 1/1 green Insect creature tokens.

Foundry Hornet

Flying
When Foundry Hornet enters, if you control a creature with a +1/+1 counter on it, creatures your opponents control get -1/-1 until end of turn.

Deadly Insect

Shroud (This creature can't be the target of spells or abilities.)

Invasive Species

When Invasive Species enters, return another permanent you control to its owner's hand.

Kraul Harpooner

Reach
Undergrowth — When Kraul Harpooner enters, choose up to one target creature you don't control with flying. Kraul Harpooner gets +X/+0 until end of turn, where X is the number of creature cards in your graveyard, then you may have Kraul Harpooner fight that creature.

Poison the Blade

Target creature gains deathtouch until end of turn.
Draw a card.

Bankrupt in Blood

As an additional cost to cast this spell, sacrifice two creatures.
Draw three cards.

Saber Ants

Whenever Saber Ants is dealt damage, you may create that many 1/1 green Insect creature tokens.

Hecatomb

When Hecatomb enters, sacrifice Hecatomb unless you sacrifice four creatures.
Tap an untapped Swamp you control: Hecatomb deals 1 damage to any target.

Kraul Raider

Menace (This creature can't be blocked except by two or more creatures.)

Crawling Infestation

At the beginning of your upkeep, you may mill two cards. (You may put the top two cards of your library into your graveyard.)
Whenever one or more creature cards are put into your graveyard from anywhere during your turn, create a 1/1 green Insect creature token. This ability triggers only once each turn.

Heartstabber Mosquito

Kicker {2}{B} (You may pay an additional {2}{B} as you cast this spell.)
Flying
When Heartstabber Mosquito enters, if it was kicked, destroy target creature.

Skittering Heartstopper

{B}: Skittering Heartstopper gains deathtouch until end of turn.

Explore

You may play an additional land this turn.
Draw a card.

Witch's Cauldron

{1}{B}, {T}, Sacrifice a creature: You gain 1 life and draw a card.

Mortipede

{2}{G}: All creatures able to block Mortipede this turn do so.

Font of Return

{3}{B}, Sacrifice Font of Return: Return up to three target creature cards from your graveyard to your hand.

Pincher Beetles

Bond Beetle

When Bond Beetle enters, put a +1/+1 counter on target creature.

Nantuko Husk

Sacrifice a creature: Nantuko Husk gets +2/+2 until end of turn.

Verdant Rebirth

Until end of turn, target creature gains "When this creature dies, return it to its owner's hand."
Draw a card.

Fog of Gnats

Plague Fiend

Whenever Plague Fiend deals combat damage to a creature, destroy that creature unless its controller pays {2}.

Altar's Reap

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

Venomous Dragonfly

Flying
Whenever Venomous Dragonfly blocks or becomes blocked by a creature, destroy that creature at end of combat.