Blister Beetle

When Blister Beetle enters, target creature gets -1/-1 until end of turn.

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.

Battlefly Swarm

Flying
{B}: Battlefly Swarm gains deathtouch until end of turn.

Bayou Dragonfly

Flying; swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Duskshell Crawler

When Duskshell Crawler enters, put a +1/+1 counter on target creature.
Each creature you control with a +1/+1 counter on it has trample.

Caustic Caterpillar

{1}{G}, Sacrifice Caustic Caterpillar: Destroy target artifact or enchantment.

Bond Beetle

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

Ironshell Beetle

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

Nantuko Vigilante

Morph {1}{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.)
When Nantuko Vigilante is turned face up, destroy target artifact or enchantment.

Plague Beetle

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Golgari Longlegs

Giant Cockroach

Pincher Beetles

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

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.

Deadly Grub

Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Deadly Grub dies, if it had no time counters on it, create a 6/1 green Insect creature token with shroud. (It can't be the target of spells or abilities.)