Infectious Inquiry

You draw two cards and you lose 2 life. Each opponent gets a poison counter.

Venomous Brutalizer

Toxic 3 (Players dealt combat damage by this creature also get three poison counters.)
When Venomous Brutalizer enters, you may pay {1}{G}. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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.)

Noxious Assault

Creatures you control get +2/+2 until end of turn. Whenever a creature blocks this turn, its controller gets a poison counter.

Necrogen Rotpriest

Toxic 2 (Players dealt combat damage by this creature also get two poison counters.)
Whenever a creature you control with toxic deals combat damage to a player, that player gets an additional poison counter.
{1}{B}{G}: Target creature you control with toxic gains deathtouch until end of turn.

Blightbelly Rat

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

Plague Nurse

Toxic 2
{2}{G}: Each other creature you control with toxic gains toxic 1 until end of turn. Activate only once each turn. (A player dealt combat damage by a creature with toxic also gets poison counters equal to that creature's total toxic value.)

Bilious Skulldweller

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

Carnivorous Canopy

Destroy target artifact, enchantment, or creature with flying. If that permanent's mana value was 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Thirsting Roots

Choose one —
• Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Nimraiser Paladin

Toxic 2 (Players dealt combat damage by this creature also get two poison counters.)
When Nimraiser Paladin enters, return target creature card with mana value 3 or less from your graveyard to your hand.

Swamp

Vraska's Fall

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

Paladin of Predation

Toxic 6 (Players dealt combat damage by this creature also get six poison counters.)
Paladin of Predation can't be blocked by creatures with power 2 or less.

Vat Emergence

Put target creature card from a graveyard onto the battlefield under your control. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Expand the Sphere

Look at the top six cards of your library. Put up to two land cards from among them onto the battlefield tapped and the rest on the bottom of your library in a random order. If you put fewer than two lands onto the battlefield this way, proliferate a number of times equal to the difference. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Ichorspit Basilisk

Tyrranax Atrocity

Haste
Toxic 3 (Players dealt combat damage by this creature also get three poison counters.)

Necrogen Communion

Enchant creature you control
Enchanted creature has toxic 2. (Players dealt combat damage by it also get two poison counters.)
When enchanted creature dies, return that card to the battlefield under your control.

Forest

Sheoldred's Headcleaver

Menace
Toxic 2 (Players dealt combat damage by this creature also get two poison counters.)