Eternal Witness

When Eternal Witness enters, you may return target card from your graveyard to your hand.

Skithiryx, the Blight Dragon

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{B}: Skithiryx, the Blight Dragon gains haste until end of turn.
{B}{B}: Regenerate Skithiryx.

Viscera Seer

Sacrifice a creature: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Prossh, Skyraider of Kher

When you cast this spell, create X 0/1 red Kobold creature tokens named Kobolds of Kher Keep, where X is the amount of mana spent to cast it.
Flying
Sacrifice another creature: Prossh, Skyraider of Kher gets +1/+0 until end of turn.

Xenagos, God of Revels

Indestructible
As long as your devotion to red and green is less than seven, Xenagos isn't a creature.
At the beginning of combat on your turn, another target creature you control gains haste and gets +X/+X until end of turn, where X is that creature's power.

Anger

Haste
As long as Anger is in your graveyard and you control a Mountain, creatures you control have haste.

Pitiless Plunderer

Whenever another creature you control dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Ashnod's Altar

Dockside Extortionist

When Dockside Extortionist enters, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")