Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Flensing Raptor

Flying
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When this creature enters, another target creature you control with toxic gets +1/+1 and gains flying until end of turn.

Mondrak, Glory Dominus

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
{1}{W/P}{W/P}, Sacrifice two other artifacts and/or creatures: Put an indestructible counter on Mondrak. ({W/P} can be paid with either {W} or 2 life.)

Blightbelly Rat

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When this creature dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Plains

Mite Overseer

First strike
During your turn, creature tokens you control get +1/+0 and have first strike.
{3}{W/P}: Create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and "This token can't block." (Players dealt combat damage by it also get a poison counter. {W/P} can be paid with either {W} or 2 life.)

Tainted Strike

Target creature gets +1/+0 and gains infect until end of turn. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Crawling Chorus

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
When this creature dies, create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and "This token can't block."

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.)

Skrelv, Defector Mite

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Skrelv can't block.
{W/P}, {T}: Choose a color. Another target creature you control gains toxic 1 and hexproof from that color until end of turn. It can't be blocked by creatures of that color this turn. ({W/P} can be paid with either {W} or 2 life.)

Pestilent Syphoner

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

The Seedcore

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast Phyrexian creature spells.
Corrupted — {T}: Target 1/1 creature gets +2/+1 until end of turn. Activate only if an opponent has three or more poison counters.

Whisper of the Dross

Target creature gets -1/-1 until end of turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Skrelv's Hive

At the beginning of your upkeep, you lose 1 life and create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and "This token can't block."
Corrupted — As long as an opponent has three or more poison counters, creatures you control with toxic have lifelink.

Swamp

Charge of the Mites

Choose one —
• Charge of the Mites deals damage equal to the number of creatures you control to target creature or planeswalker.
• Create two 1/1 colorless Phyrexian Mite artifact creature tokens with toxic 1 and "This token can't block." (Players dealt combat damage by them also get a poison counter.)

Mirrex

{T}: Add {C}.
{T}: Add one mana of any color. Activate only if this land entered this turn.
{3}, {T}: Create a 1/1 colorless Phyrexian Mite artifact creature token with toxic 1 and "This token can't block." (Players dealt combat damage by it also get a poison counter.)

Sheoldred's Edict

Choose one —
• Each opponent sacrifices a nontoken creature of their choice.
• Each opponent sacrifices a creature token of their choice.
• Each opponent sacrifices a planeswalker of their choice.

Vraska's Fall

Each opponent sacrifices a creature or planeswalker of their choice and gets a poison counter.

Skorpekh Lord

Menace
Command Protocols — Other artifact creatures you control get +1/+0 and have menace.
Unearth {2}{B} ({2}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Bilious Skulldweller

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

Jawbone Duelist

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

Drown in Ichor

Target creature gets -4/-4 until end of turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)