Blightwidow

Reach (This creature can block creatures with flying.)
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Aatchik, Emerald Radian

When Aatchik enters, create a 1/1 green Insect creature token for each artifact and/or creature card in your graveyard.
Whenever another Insect you control dies, put a +1/+1 counter on Aatchik. Each opponent loses 1 life.

Broodguard Elite

This creature enters with X +1/+1 counters on it.
When this creature leaves the battlefield, put its counters on target creature you control.
Warp {X}{G} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Blade of the Swarm

When this creature enters, choose one —
• Put two +1/+1 counters on this creature.
• Put target exiled card with warp on the bottom of its owner's library.

Blood Artist

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

Broodspinner

Reach
When this creature enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
{4}{B}{G}, {T}, Sacrifice this creature: Create a number of 1/1 black and green Insect creature tokens with flying equal to the number of card types among cards in your graveyard.

Archweaver

The Swarmweaver

When The Swarmweaver enters, create two 1/1 black and green Insect creature tokens with flying.
Delirium — As long as there are four or more card types among cards in your graveyard, Insects and Spiders you control get +1/+1 and have deathtouch.

Arachnoid

Reach (This creature can block creatures with flying.)

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.

Ant Queen

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

Arasta of the Endless Web

Reach
Whenever an opponent casts an instant or sorcery spell, create a 1/2 green Spider creature token with reach.

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.)

Increasing Savagery

Put five +1/+1 counters on target creature. If this spell was cast from a graveyard, put ten +1/+1 counters on that creature instead.
Flashback {5}{G}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)