Keyword: Proliferate

Protection from Humans
Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card.
, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

When Contagion Clasp enters the battlefield, 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.)

When Contagion Engine enters the battlefield, put a -1/-1 counter on each creature target player controls.
, : Proliferate, then proliferate again. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Whenever a land enters the battlefield under your control, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

, Sacrifice an artifact: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Flying, vigilance, deathtouch, lifelink
At the beginning of your end step, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Flying, vigilance, deathtouch, lifelink
At the beginning of your end step, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

When Pollenbright Druid enters the battlefield, 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.)

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

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

Flying
Whenever Thrummingbird 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.)

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.)

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

When Contagion Clasp enters the battlefield, 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.)

( can be paid with either or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Equipped creature gets +2/+2 and has protection from white and from blue.
Whenever equipped creature deals combat damage to a player, put a +1/+1 counter on a creature you control, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Equip

Protection from Humans
Pay 1 life, Sacrifice another creature: Put a -1/-1 counter on up to one target creature and draw a card.
, Discard a card: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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

Flying, trample
When Roalesk, Apex Hybrid enters the battlefield, put two +1/+1 counters on another target creature you control.
When Roalesk dies, proliferate, then proliferate again. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

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

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

Choose four. You may choose the same mode more than once.
• Create a 2/2 Citizen creature token that’s all colors.
• Return target permanent card from your graveyard to your hand.
• Proliferate.
• You gain 4 life.

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

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

Flying
When Merfolk Skydiver enters the battlefield, put a +1/+1 counter on target creature you control.
: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)