Myr Scrapling

Sacrifice Myr Scrapling: Put a +1/+1 counter on target creature.

Unleash Fury

Double the power of target creature until end of turn.

Geralf's Messenger

Geralf's Messenger enters tapped.
When Geralf's Messenger enters, target opponent loses 2 life.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Gravecrawler

Gravecrawler can't block.
You may cast Gravecrawler from your graveyard as long as you control a Zombie.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Chandra's Ignition

Target creature you control deals damage equal to its power to each other creature and each opponent.

Orca, Siege Demon

Trample
Whenever another creature dies, put a +1/+1 counter on Orca, Siege Demon.
When Orca dies, it deals damage equal to its power divided as you choose among any number of targets.