Consider

Rot Farm Mortipede

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

Culling Ritual

Destroy each nonland permanent with mana value 2 or less. Add {B} or {G} for each permanent destroyed this way.

In Deck

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 Spring-Leaf Avenger deals combat damage to a player, return target permanent card from your graveyard to your hand.

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Insidious Roots

Creature tokens you control have "{T}: Add one mana of any color."
Whenever one or more creature cards leave your graveyard, create a 0/1 green Plant creature token, then put a +1/+1 counter on each Plant you control.

Hornet Nest

Defender (This creature can't attack.)
Whenever Hornet Nest 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.)

Mortician Beetle

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

Swamp

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.

Nantuko Husk

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

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.

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}.

Undergrowth Stadium

Undergrowth Stadium enters tapped unless you have two or more opponents.
{T}: Add {B} or {G}.

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}.)

Marker Beetles

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

Phantom Nantuko

Trample
Phantom Nantuko enters with two +1/+1 counters on it.
If damage would be dealt to Phantom Nantuko, prevent that damage. Remove a +1/+1 counter from Phantom Nantuko.
{T}: Put a +1/+1 counter on Phantom Nantuko.

Rotfeaster Maggot

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

Path of Ancestry

Path of Ancestry enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Grisly Salvage

Reveal the top five cards of your library. You may put a creature or land card from among them into your hand. Put the rest into your graveyard.

The Hunger Tide Rises

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I, II, III — Create a 1/1 black and green Insect creature token.
IV — Sacrifice any number of creatures. Search your library and/or graveyard for a creature card with mana value less than or equal to the number of creatures sacrificed this way and put it onto the battlefield. If you search your library this way, shuffle.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Formless Genesis

Changeling (This card is every creature type.)
Create an X/X colorless Shapeshifter creature token with changeling and deathtouch, where X is the number of land cards in your graveyard.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

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.)

Entish Restoration

Sacrifice a land. Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle. If you control a creature with power 4 or greater, instead search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

Llanowar Wastes

{T}: Add {C}.
{T}: Add {B} or {G}. Llanowar Wastes deals 1 damage to you.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

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.

Necrosquito

Flying
Necrosquito enters with two oil counters on it.
Necrosquito gets +1/+1 for each oil counter on it.
Whenever another creature or artifact you control is put into a graveyard from the battlefield, put an oil counter on Necrosquito.

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. (It can deal excess combat damage to the player or planeswalker it's attacking.)

Anthropede

Reach
When Anthropede enters, you may discard a card or pay {2}. When you do, destroy target Room.

Command Tower

Living Hive

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

Bane of the Living

Morph {X}{B}{B} (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 Bane of the Living is turned face up, all creatures get -X/-X until end of turn.

Moldervine Reclamation

Whenever a creature you control dies, you gain 1 life and draw a card.

Verdant Succession

Whenever a green nontoken creature dies, that creature's controller may search their library for a card with the same name as that creature, put it onto the battlefield, then shuffle.

Saber Ants

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

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Golgari Rot Farm

Golgari Rot Farm enters tapped.
When Golgari Rot Farm enters, return a land you control to its owner's hand.
{T}: Add {B}{G}.

Cultivate

Plague Beetle

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

Blister Beetle

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

Nantuko Cultivator

When Nantuko Cultivator enters, you may discard any number of land cards. Put that many +1/+1 counters on Nantuko Cultivator and draw that many cards.

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

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.)

Battlefly Swarm

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

Woodland Cemetery

Woodland Cemetery enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Scute Mob

At the beginning of your upkeep, if you control five or more lands, put four +1/+1 counters on Scute Mob.

Three Tree Mascot

Changeling (This card is every creature type.)
{1}: Add one mana of any color. Activate only once each turn.

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

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, Voracious Larva 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

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.)

Forest

Hornet Queen

Flying, deathtouch
When Hornet Queen enters, create four 1/1 green Insect creature tokens with flying and deathtouch.

Mazirek, Kraul Death Priest

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

Ant Queen

{1}{G}: Create a 1/1 green Insect creature token.

Nantuko Elder

Ironshell Beetle

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

Xantid Swarm

Flying
Whenever Xantid Swarm attacks, defending player can't cast spells this turn.

Swarmyard Massacre

Create two 1/1 green Squirrel creature tokens. Then each creature that isn't an Insect, Rat, Spider, or Squirrel gets -1/-1 until end of turn for each creature you control that's an Insect, Rat, Spider, or Squirrel.

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.

Huskburster Swarm

This spell costs {1} less to cast for each creature card you own in exile and in your graveyard.
Menace, deathtouch

Necropede

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Necropede dies, you may put a -1/-1 counter on target creature.

Giant Ladybug

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

Beacon of Creation

Create a 1/1 green Insect creature token for each Forest you control. Shuffle Beacon of Creation into its owner's library.

Crop Rotation

As an additional cost to cast this spell, sacrifice a land.
Search your library for a land card, put that card onto the battlefield, then shuffle.

Ranger Class

(Gain the next level as a sorcery to add its ability.)
When Ranger Class enters, create a 2/2 green Wolf creature token.
{1}{G}: Level 2
Whenever you attack, put a +1/+1 counter on target attacking creature.
{3}{G}: Level 3
You may look at the top card of your library any time.
You may cast creature spells from the top of your library.

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.

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.

Haywire Mite

When Haywire Mite dies, you gain 2 life.
{G}, Sacrifice Haywire Mite: Exile target noncreature artifact or noncreature enchantment.

Virus Beetle

When Virus Beetle enters, each opponent discards a card.

Blasphemous Edict

You may pay {B} rather than pay this spell's mana cost if there are thirteen or more creatures on the battlefield.
Each player sacrifices thirteen creatures of their choice.

Crawling Sensation

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 land cards are put into your graveyard from anywhere for the first time each turn, create a 1/1 green Insect creature token.

Village Rites

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

Crash of Rhino Beetles

Trample
Crash of Rhino Beetles gets +10/+10 as long as you control ten or more lands.

Dross Hopper

Sacrifice a creature: Dross Hopper gains flying until end of turn.

Communal Brewing

When Communal Brewing enters, any number of target opponents each draw a card. Put an ingredient counter on Communal Brewing, then put an ingredient counter on it for each card drawn this way.
Whenever you cast a creature spell, that creature enters with X additional +1/+1 counters on it, where X is the number of ingredient counters on Communal Brewing.

Kazandu Nectarpot

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

Moldgraf Millipede

When Moldgraf Millipede enters, mill three cards, then put a +1/+1 counter on Moldgraf Millipede for each creature card in your graveyard. (To mill three cards, put the top three cards of your library into your graveyard.)

Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

Bond Beetle

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

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.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Skylasher

Flash
This spell can't be countered.
Reach, protection from blue

Springheart Nantuko

Bestow {1}{G}
Enchanted creature gets +1/+1.
Landfall — Whenever a land you control enters, you may pay {1}{G} if Springheart Nantuko 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.

Circuit Mender

When Circuit Mender enters, you gain 2 life.
When Circuit Mender leaves the battlefield, draw a card.

Grist, the Hunger Tide

As long as Grist, the Hunger Tide isn't on the battlefield, it's a 1/1 Insect creature in addition to its other types.
+1: Create a 1/1 black and green Insect creature token, then mill a card. If an Insect card was milled this way, put a loyalty counter on Grist and repeat this process.
−2: You may sacrifice a creature. When you do, destroy target creature or planeswalker.
−5: Each opponent loses life equal to the number of creature cards in your graveyard.

Stag Beetle

Stag Beetle enters with X +1/+1 counters on it, where X is the number of other creatures on the battlefield.

Sol Ring

Coiling Woodworm

Coiling Woodworm's power is equal to the number of Forests on the battlefield.

Primordial Gnawer

When Primordial Gnawer dies, discover 3. (Exile cards from the top of your library until you exile a nonland card with mana value 3 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)

Caustic Wasps

Flying
Whenever Caustic Wasps deals combat damage to a player, you may destroy target artifact that player controls.

Squirming Emergence

Fathomless descent — Return to the battlefield target nonland permanent card in your graveyard with mana value less than or equal to the number of permanent cards in your graveyard.

Hedge Shredder

Whenever Hedge Shredder attacks, you may mill two cards.
Whenever one or more land cards are put into your graveyard from your library, put them onto the battlefield tapped.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

Spinal Centipede

When Spinal Centipede dies, put a +1/+1 counter on target creature you control.

Carrion Locust

Flying
When Carrion Locust enters, exile target card from an opponent's graveyard. If it was a creature card, that player loses 1 life.

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.

Carrion Grub

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

Skittering Heartstopper

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

Caustic Caterpillar

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

Flesh Burrower

Deathtouch
Whenever Flesh Burrower attacks, another target creature you control gains deathtouch until end of turn.

Plague Fiend

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