Fog of Gnats

Ferropede

This creature can't be blocked.
Whenever this creature deals combat damage to a player, you may remove a counter from target permanent.

Giant Caterpillar

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

Arcbound Stinger

Flying
Modular 1 (This creature enters with a +1/+1 counter on it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Bond Beetle

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

Hex Parasite

{X}{B/P}: Remove up to X counters from target permanent. For each counter removed this way, this creature gets +1/+0 until end of turn. ({B/P} can be paid with either {B} or 2 life.)

Nessian Hornbeetle

At the beginning of combat on your turn, if you control another creature with power 4 or greater, put a +1/+1 counter on this creature.

Blightbeetle

Protection from green (This creature can't be blocked, targeted, dealt damage, enchanted, or equipped by anything green.)
Creatures your opponents control can't have +1/+1 counters put on them.

Kraul Whipcracker

Reach
When this creature enters, destroy target token an opponent controls.

Rot Farm Mortipede

Whenever one or more creature cards leave your graveyard, this creature gets +1/+0 and gains menace and lifelink until end of turn.

Grist, the Plague Swarm

+1: Create a 1/1 black and green Insect creature token, then mill two cards. Put a deathtouch counter on the token if a black card was milled this way.
−2: Destroy target artifact or enchantment.
−6: For each creature card in your graveyard, create a token that's a copy of it, except it's a 1/1 black and green Insect.

Grist, Voracious Larva

Deathtouch
Whenever Grist or another creature you control enters, if it entered from your graveyard or you cast it from your graveyard, you may pay {G}. If you do, exile Grist, then return it to the battlefield transformed under its owner's control.

Grist, Voracious Larva // Grist, the Plague Swarm

Pestilent Syphoner

Flying
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)

Atraxa's Skitterfang

This creature enters with three oil counters on it.
At the beginning of combat on your turn, you may remove an oil counter from this creature. When you do, target creature you control gains your choice of flying, vigilance, deathtouch, or lifelink until end of turn.

Infesting Radroach

Flying
This creature can't block.
Whenever this creature deals combat damage to a player, they get that many rad counters.
Whenever an opponent mills a nonland card, if this creature is in your graveyard, you may return it to your hand.

Carrion Grub

This creature gets +X/+0, where X is the greatest power among creature cards in your graveyard.
When this creature enters, mill four cards. (Put the top four cards of your library into your graveyard.)

Duskshell Crawler

When this creature enters, put a +1/+1 counter on target creature.
Each creature you control with a +1/+1 counter on it has trample. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Flow of Maggots

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
This creature can't be blocked by non-Wall creatures.

Plague Stinger

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Ambush Krotiq

Trample
When this creature enters, return another creature you control to its owner's hand.

Kraul Harpooner

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

Mazirek, Kraul Death Priest

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

Virus Beetle

When this creature enters, each opponent discards a card.

Canoptek Scarab Swarm

Flying
Feeder Mandibles — When this creature enters, exile target player's graveyard. For each artifact or land card exiled this way, create a 1/1 colorless Insect artifact creature token with flying.

Giant Ankheg

Trample
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Other creatures you control have trample and ward {2}.

Hornet Nest

Defender (This creature can't attack.)
Whenever this creature is dealt damage, create that many 1/1 green Insect creature tokens with flying and deathtouch. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.)

Quarry Beetle

When this creature enters, you may return target land card from your graveyard to the battlefield.

Lattice-Blade Mantis

This creature enters with two oil counters on it.
Whenever this creature attacks, you may remove an oil counter from it. If you do, untap it and it gets +1/+1 until end of turn.

Plague Fiend

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

Fen Hauler

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Fen Hauler can't be blocked by artifact creatures.

Living Hive

Trample
Whenever this creature deals combat damage to a player, create that many 1/1 green Insect creature tokens.

Devouring Swarm

Flying
Sacrifice a creature: This creature gets +1/+1 until end of turn.

Clockwork Beetle

This creature enters with two +1/+1 counters on it.
Whenever this creature attacks or blocks, remove a +1/+1 counter from it at end of combat.

Jhoira's Timebug

{T}: Choose target permanent you control or suspended card you own. If that permanent or card has a time counter on it, you may remove a time counter from it or put another time counter on it.

Plague Beetle

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

Spring-Leaf Avenger

Ninjutsu {3}{G} ({3}{G}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
Whenever this creature deals combat damage to a player, return target permanent card from your graveyard to your hand.

Caustic Caterpillar

{1}{G}, Sacrifice this creature: Destroy target artifact or enchantment.

Crash of Rhino Beetles

Trample
This creature gets +10/+10 as long as you control ten or more lands.

Bilious Skulldweller

Deathtouch
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)

Stinging Cave Crawler

Deathtouch
Descend 4 — Whenever this creature attacks, if there are four or more permanent cards in your graveyard, you draw a card and you lose 1 life.

Nantuko Shaman

When Nantuko Shaman enters, if you control no tapped lands, draw a card.
Suspend 1—{2}{G}{G} (Rather than cast this card from your hand, you may pay {2}{G}{G} and exile it with a time counter on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)

Brain Weevil

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Sacrifice this creature: Target player discards two cards. Activate only as a sorcery.

Carrion Beetles

{2}{B}, {T}: Exile up to three target cards from a single graveyard.

Giant Ladybug

Reach
When this creature enters, you may search your library for a basic land card, reveal it, then shuffle and put that card on top.

Swarm of Bloodflies

Flying
This creature enters with two +1/+1 counters on it.
Whenever another creature dies, put a +1/+1 counter on this creature.

Skittering Heartstopper

{B}: This creature gains deathtouch until end of turn.

Acridian

Echo {1}{G} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)

Foundry Hornet

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

Nantuko Husk

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

Gigapede

Shroud (This creature can't be the target of spells or abilities.)
At the beginning of your upkeep, if this card is in your graveyard, you may discard a card. If you do, return this card to your hand.

Ambush Gigapede

Flash
When this creature enters, target creature an opponent controls gets -2/-2 until end of turn.

Saber Ants

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

Stirge

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

Brain Maggot

When this creature enters, target opponent reveals their hand and you choose a nonland card from it. Exile that card until this creature leaves the battlefield.

Battlefly Swarm

Flying
{B}: This creature gains deathtouch until end of turn.

Scute Swarm

Landfall — Whenever a land you control enters, create a 1/1 green Insect creature token. If you control six or more lands, create a token that's a copy of this creature instead.

Mortipede

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

Giant Cockroach

Goliath Beetle

Dross Hopper

Sacrifice a creature: This creature gains flying until end of turn.

Gleancrawler

({B/G} can be paid with either {B} or {G}.)
Trample
At the beginning of your end step, return to your hand all creature cards in your graveyard that were put there from the battlefield this turn.

Kazandu Nectarpot

Landfall — Whenever a land you control enters, you gain 1 life.

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 this creature 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.)

Kraul Foragers

Undergrowth — When this creature enters, you gain 1 life for each creature card in your graveyard.

Mortician Beetle

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

Zask, Skittering Swarmlord

You may play lands and cast Insect spells from your graveyard.
Whenever another Insect you control dies, put it on the bottom of its owner's library, then mill two cards. (Put the top two cards of your library into your graveyard.)
{1}{B/G}: Target Insect gets +1/+0 and gains deathtouch until end of turn. ({B/G} can be paid with either {B} or {G}.)

Amzu, Swarm's Hunger

Flying, menace
Other Insects you control have menace.
Whenever one or more cards leave your graveyard, you may create a 1/1 black and green Insect creature token, then put a number of +1/+1 counters on it equal to the greatest mana value among those cards. Do this only once each turn.

Jhoira's Toolbox

{2}: Regenerate target artifact creature.

Springheart Nantuko

Bestow {1}{G}
Enchanted creature gets +1/+1.
Landfall — Whenever a land you control enters, you may pay {1}{G} if this permanent is attached to a creature you control. If you do, create a token that's a copy of that creature. If you didn't create a token this way, create a 1/1 green Insect creature token.

Bloatfly Swarm

Flying
This creature enters with five +1/+1 counters on it.
If damage would be dealt to this creature while it has a +1/+1 counter on it, prevent that damage, remove that many +1/+1 counters from it, then give each player a rad counter for each +1/+1 counter removed this way.

Nantuko Tracer

When this creature enters, you may put target card from a graveyard on the bottom of its owner's library.

Giant Adephage

Trample
Whenever this creature deals combat damage to a player, create a token that's a copy of this creature.

Broodhatch Nantuko

Whenever this creature 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.)