Deathless Knight

Haste
When you gain life for the first time each turn, return Deathless Knight from your graveyard to your hand.

Death Tyrant

Menace
Negative Energy Cone — Whenever an attacking creature you control or a blocking creature an opponent controls dies, create a 2/2 black Zombie creature token.
{5}{B}: Return Death Tyrant from your graveyard to the battlefield tapped.

Bone Rattler

When Bone Rattler is put into your graveyard from anywhere, exile it. When you do, create four Reassembling Skeleton token cards and put them into your graveyard.

Clattering Augur

Clattering Augur can't block.
When Clattering Augur enters, you draw a card and you lose 1 life.
{2}{B}{B}: Return Clattering Augur from your graveyard to your hand.