Have

Core Prowler

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When Core Prowler dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Pollenbright Druid

When Pollenbright Druid enters, choose one —
• Put a +1/+1 counter on target creature.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Contagion Clasp

When Contagion Clasp enters, put a -1/-1 counter on target creature.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Phyrexian Digester

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Viral Drake

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Island

Steady Progress

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

Chained Throatseeker

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Chained Throatseeker can't attack unless defending player is poisoned.

Simic Guildgate

This land enters tapped.
{T}: Add {G} or {U}.

Simic Cluestone

{T}: Add {G} or {U}.
{G}{U}, {T}, Sacrifice Simic Cluestone: Draw a card.

Nafs Asp

Whenever Nafs Asp deals damage to a player, that player loses 1 life at the beginning of their next draw step unless they pay {1} before that draw step.

Fuel for the Cause

Counter target spell, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Spinebiter

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
You may have Spinebiter assign its combat damage as though it weren't blocked.

Rot Wolf

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
Whenever a creature dealt damage by Rot Wolf this turn dies, you may draw a card.

Twiddle

You may tap or untap target artifact, creature, or land.

Leeching Bite

Target creature gets +1/+1 until end of turn. Another target creature gets -1/-1 until end of turn.

Trigon of Infestation

Trigon of Infestation enters with three charge counters on it.
{G}{G}, {T}: Put a charge counter on Trigon of Infestation.
{2}, {T}, Remove a charge counter from Trigon of Infestation: Create a 1/1 green Phyrexian Insect creature token with infect.

Courage in Crisis

Put a +1/+1 counter on target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Mycosynth Fiend

Mycosynth Fiend gets +1/+1 for each poison counter your opponents have.

New Horizons

Enchant land
When this Aura enters, put a +1/+1 counter on target creature you control.
Enchanted land has "{T}: Add two mana of any one color."

Naturalize

Forest

Cystbearer

Forced Landing

Put target creature with flying on the bottom of its owner's library.

Glistener Elf

Stealth Mission

Put two +1/+1 counters on target creature you control. That creature can't be blocked this turn.

Plaguemaw Beast

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

Kiora's Dambreaker

When Kiora's Dambreaker enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Corrupted Conscience

Enchant creature
You control enchanted creature.
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Viridian Betrayers

Viridian Betrayers has infect as long as an opponent is poisoned. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

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.)
Blighted Agent can't be blocked.

Bloom Hulk

When Bloom Hulk enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Phyrexian Swarmlord

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
At the beginning of your upkeep, create a 1/1 green Phyrexian Insect creature token with infect for each poison counter your opponents have.

Wall of Tanglecord

Defender
{G}: Wall of Tanglecord gains reach until end of turn. (It can block creatures with flying.)

Giant Spider

Reach (This creature can block creatures with flying.)

Evolution Sage

Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)