Have (Arena)

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Cinder Barrens

Cinder Barrens enters tapped.
{T}: Add {B} or {R}.

Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Rekindling Phoenix

Flying
When Rekindling Phoenix dies, create a 0/1 red Elemental creature token with "At the beginning of your upkeep, sacrifice this creature and return target card named Rekindling Phoenix from your graveyard to the battlefield. It gains haste until end of turn."

Brawl-Bash Ogre

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Brawl-Bash Ogre attacks, you may sacrifice another creature. If you do, Brawl-Bash Ogre gets +2/+2 until end of turn.

Ravenous Harpy

Flying
{1}, Sacrifice another creature: Put a +1/+1 counter on Ravenous Harpy.

Demon of Catastrophes

As an additional cost to cast this spell, sacrifice a creature.
Flying, trample

Siege-Gang Commander

When Siege-Gang Commander enters, create three 1/1 red Goblin creature tokens.
{1}{R}, Sacrifice a Goblin: Siege-Gang Commander deals 2 damage to any target.

Murder

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Gravedigger

When Gravedigger enters, you may return target creature card from your graveyard to your hand.

Doomed Dissenter

When Doomed Dissenter dies, create a 2/2 black Zombie creature token.

Goblin Instigator

When Goblin Instigator enters, create a 1/1 red Goblin creature token.

Goblin Trashmaster

Other Goblins you control get +1/+1.
Sacrifice a Goblin: Destroy target artifact.

Blood Divination

As an additional cost to cast this spell, sacrifice a creature.
Draw three cards.

Open the Graves

Whenever a nontoken creature you control dies, create a 2/2 black Zombie creature token.

Gravewaker

Flying (This creature can't be blocked except by creatures with flying or reach.)
{5}{B}{B}: Return target creature card from your graveyard to the battlefield tapped.