Vraska, Swarm's Eminence

Whenever a creature you control with deathtouch deals damage to a player or planeswalker, put a +1/+1 counter on that creature.
−2: Create a 1/1 black Assassin creature token with deathtouch and "Whenever this token deals damage to a planeswalker, destroy that planeswalker."

Infectious Bite

Target creature you control deals damage equal to its power to target creature you don't control. Each opponent gets a poison counter.

Fynn, the Fangbearer

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever a creature you control with deathtouch deals combat damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)

Infectious Inquiry

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

Unnatural Restoration

Return target permanent card from your graveyard to your hand. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Viral Spawning

Create a 3/3 green Phyrexian Beast creature token with toxic 1. (Players dealt combat damage by it also get a poison counter.)
Corrupted — As long as an opponent has three or more poison counters and this card is in your graveyard, it has flashback {2}{G}. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Tyvar's Stand

Target creature you control gets +X/+X and gains hexproof and indestructible until end of turn. (A creature with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Swamp

March of Burgeoning Life

As an additional cost to cast this spell, you may exile any number of green cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Choose target creature with mana value less than X. Search your library for a creature card with the same name as that creature, put it onto the battlefield tapped, then shuffle.

Tablet of Compleation

{T}: Put an oil counter on this artifact.
{T}: Add {C}. Activate only if this artifact has two or more oil counters on it.
{1}, {T}: Draw a card. Activate only if this artifact has five or more oil counters on it.

Bloated Contaminator

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

Woodland Cemetery

This land enters tapped unless you control a Swamp or a Forest.
{T}: Add {B} or {G}.

Hissing Quagmire

This land enters tapped.
{T}: Add {B} or {G}.
{1}{B}{G}: Until end of turn, this land becomes a 2/2 black and green Elemental creature with deathtouch. It's still a land.

Branchblight Stalker

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

Ichorspit Basilisk

Deathtouch
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.)

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.)

Anoint with Affliction

Exile target creature if it has mana value 3 or less.
Corrupted — Exile that creature instead if its controller has three or more poison counters.

Venerated Rotpriest

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever a creature you control becomes the target of a spell, target opponent gets a poison counter.

Lead by Example

Support 2. (Put a +1/+1 counter on each of up to two target creatures.)

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.)

Shapers' Sanctuary

Whenever a creature you control becomes the target of a spell or ability an opponent controls, you may draw a card.

Warriors' Lesson

Until end of turn, up to two target creatures you control each gain "Whenever this creature deals combat damage to a player, draw a card."

Forest

Pestilent Syphoner

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

Llanowar Wastes

{T}: Add {C}.
{T}: Add {B} or {G}. This land deals 1 damage to you.

Vraska's Fall

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