Vito, Thorn of the Dusk Rose

Whenever you gain life, target opponent loses that much life.
{3}{B}{B}: Creatures you control gain lifelink until end of turn.

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Mindslaver

{4}, {T}, Sacrifice Mindslaver: You control target player during that player's next turn. (You see all cards that player could see and make all decisions for them.)

Radstorm

Storm (When you cast this spell, copy it for each spell cast before it this turn.)
Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Winter, Cynical Opportunist

Deathtouch
Whenever Winter attacks, mill three cards.
Delirium — At the beginning of your end step, you may exile any number of cards from your graveyard with four or more card types among them. If you do, put a permanent card from among them onto the battlefield with a finality counter on it.

The Wise Mothman

Flying
Whenever The Wise Mothman enters or attacks, each player gets a rad counter.
Whenever one or more nonland cards are milled, put a +1/+1 counter on each of up to X target creatures, where X is the number of nonland cards milled this way.

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

Blood Artist

Whenever this creature or another creature dies, target player loses 1 life and you gain 1 life.