Offer Immortality

Target creature gains deathtouch and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Scheming Aspirant

Whenever you proliferate, each opponent loses 2 life and you gain 2 life.

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.)

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.

Tyrranax Atrocity

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

Maze Skullbomb

{1}, Sacrifice this artifact: Draw a card.
{2}{G}, Sacrifice this artifact: Target creature you control gets +3/+3 and gains trample until end of turn. Draw a card. Activate only as a sorcery.

Fleshless Gladiator

Corrupted — {2}{B}: Return this card from your graveyard to the battlefield tapped. You lose 1 life. Activate only if an opponent has three or more poison counters.

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.)

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.)

Pestilent Syphoner

Flying
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.)

Swamp

Paladin of Predation

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

Tyvar, Jubilant Brawler

You may activate abilities of creatures you control as though those creatures had haste.
+1: Untap up to one target creature.
−2: Mill three cards, then you may return a creature card with mana value 2 or less from your graveyard to the battlefield.

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.)

Bonepicker Skirge

Flying
Corrupted — As long as an opponent has three or more poison counters, this creature has deathtouch and lifelink.

Forest

Infectious Inquiry

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

Phyrexian Obliterator

Trample
Whenever a source deals damage to this creature, that source's controller sacrifices that many permanents of their choice.