Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Krosan Grip

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Destroy target artifact or enchantment.

Honest Rutstein

When Honest Rutstein enters the battlefield, return target creature card from your graveyard to your hand.
Creature spells you cast cost {1} less to cast.

Feed the Swarm

Destroy target creature or enchantment an opponent controls. You lose life equal to that permanent's mana value.

Amulet of Vigor

Whenever a permanent enters the battlefield tapped and under your control, untap it.

Fleshbag Marauder

When Fleshbag Marauder enters the battlefield, each player sacrifices a creature.

No Mercy

Whenever a creature deals damage to you, destroy it.

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

Murder

Vraska, the Silencer

Deathtouch
Whenever a nontoken creature an opponent controls dies, you may pay {1}. If you do, return that card to the battlefield tapped under your control. It's a Treasure artifact with "{T}, Sacrifice this artifact: Add one mana of any color," and it loses all other card types.

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.