Pestilent Syphoner

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

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.)

Ironshell Beetle

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

Battlefly Swarm

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

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: 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.

Kraul Raider

Menace (This creature can't be blocked except by two or more creatures.)

Bond Beetle

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

Bilious Skulldweller

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

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.)