Mazirek, Kraul Death Priest

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

Vrestin, Menoptra Leader

Flying
Vrestin enters with X +1/+1 counters on it.
When Vrestin enters, create X 1/1 green and white Alien Insect creature tokens with flying.
Whenever you attack with one or more Insects, put a +1/+1 counter on each of them.

Hornet Queen

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

Xira Arien

Flying
{B}{R}{G}, {T}: Target player draws a card.

Hornet Cannon

{3}, {T}: Create a 1/1 colorless Insect artifact creature token with flying and haste named Hornet. Destroy it at the beginning of the next end step.

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}.)

Vizier of Remedies

If one or more -1/-1 counters would be put on a creature you control, that many -1/-1 counters minus one are put on it instead.

Hornet

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.)

Wasp of the Bitter End

Flying
Whenever you cast a Bolas planeswalker spell, you may sacrifice this creature. If you do, destroy target creature.

Zabaz, the Glimmerwasp

Modular 1
If a modular triggered ability would put one or more +1/+1 counters on a creature you control, that many plus one +1/+1 counters are put on it instead.
{R}: Destroy target artifact you control.
{W}: Zabaz gains flying until end of turn.

Prakhata Pillar-Bug

{B}: This creature gains lifelink until end of turn. (Damage dealt by this creature also causes you to gain that much life.)

Hornet Sting

Hornet Sting deals 1 damage to any target.

The Hive

{5}, {T}: Create a 1/1 colorless Insect artifact creature token with flying named Wasp. (It can't be blocked except by creatures with flying or reach.)

Adaptive Shimmerer

Flash
This creature enters with three +1/+1 counters on it.

Beetleform Mage

{G}{U}: This creature gets +2/+2 and gains flying until end of turn. Activate only once each turn.

Hornet Harasser

When this creature dies, target creature gets -2/-2 until end of turn.

Kathril, Aspect Warper

When Kathril enters, put a flying counter on any creature you control if a creature card in your graveyard has flying. Repeat this process for first strike, double strike, deathtouch, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance. Then put a +1/+1 counter on Kathril for each counter put on a creature this way.

Vishgraz, the Doomhive

Menace, toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When Vishgraz enters, create three 1/1 colorless Phyrexian Mite artifact creature tokens with toxic 1 and "This token can't block."
Vishgraz gets +1/+1 for each poison counter your opponents have.