Mardu Skullhunter

Mardu Skullhunter enters tapped.
Raid — When Mardu Skullhunter enters, if you attacked this turn, target opponent discards a card.

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.)

Mountain

Butcher of the Horde

Flying
Sacrifice another creature: Butcher of the Horde gains your choice of vigilance, lifelink, or haste until end of turn.

Debilitating Injury

Enchant creature
Enchanted creature gets -2/-2.

Throttle

Target creature gets -4/-4 until end of turn.

Nomad Outpost

Nomad Outpost enters tapped.
{T}: Add {R}, {W}, or {B}.

Swamp

Plains

Shambling Attendants

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Dutiful Return

Return up to two target creature cards from your graveyard to your hand.

Swift Kick

Target creature you control gets +1/+0 until end of turn. It fights target creature you don't control.

Jeering Instigator

Morph {2}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Jeering Instigator is turned face up, if it's your turn, gain control of another target creature until end of turn. Untap that creature. It gains haste until end of turn.

Bloodfell Caves

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {R}.

Goblinslide

Whenever you cast a noncreature spell, you may pay {1}. If you do, create a 1/1 red Goblin creature token with haste.

Bring Low

Bring Low deals 3 damage to target creature. If that creature has a +1/+1 counter on it, Bring Low deals 5 damage to it instead.

Grim Haruspex

Morph {B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
Whenever another nontoken creature you control dies, draw a card.

Arrow Storm

Arrow Storm deals 4 damage to any target.
Raid — If you attacked this turn, instead Arrow Storm deals 5 damage to that permanent or player and the damage can't be prevented.

Despise

Target opponent reveals their hand. You choose a creature or planeswalker card from it. That player discards that card.