Keyword: Proliferate

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.)

( 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.)

Volt Charge deals 3 damage to any target. 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.)

, Sacrifice a creature: 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.)

Destroy target creature, then 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.)

( 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.)

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

Volt Charge deals 3 damage to any target. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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

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

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.)

Destroy target creature, then 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.)

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

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

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.)

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 you cast a spell, 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 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.)