Vivisurgeon's Insight

Draw three cards. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Vraska's Fall

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

Prologue to Phyresis

Each opponent gets a poison counter.
Draw a card.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
This artifact enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on this artifact.

Blighted Agent

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
This creature can't be blocked.

Island

Experimental Augury

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Pentad Prism

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
Remove a charge counter from this artifact: Add one mana of any color.

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.

Ichorclaw Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever this creature becomes blocked, it gets +2/+2 until end of turn.

Bring the Ending

Counter target spell unless its controller pays {2}.
Corrupted — Counter that spell instead if its controller has three or more poison counters.

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.)

Serrated Arrows

This artifact enters with three arrowhead counters on it.
At the beginning of your upkeep, if there are no arrowhead counters on this artifact, sacrifice it.
{T}, Remove an arrowhead counter from this artifact: Put a -1/-1 counter on target creature.

Peat Bog

This land enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from this land: Add {B}{B}. If there are no depletion counters on this land, sacrifice it.

Virulent Wound

Put a -1/-1 counter on target creature. When that creature dies this turn, its controller gets a poison counter.

Birthday Escape

Swamp

Cast Down

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.)

Contentious Plan

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Nightscape Familiar

Blue spells and red spells you cast cost {1} less to cast.
{1}{B}: Regenerate this creature.

Infectious Inquiry

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

Corpse Cur

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When this creature enters, you may return target creature card with infect from your graveyard to your hand.

Snap

Return target creature to its owner's hand. Untap up to two lands.

Saprazzan Skerry

This land enters tapped with two depletion counters on it.
{T}, Remove a depletion counter from this land: Add {U}{U}. If there are no depletion counters on this land, sacrifice it.

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.)