Bump in the Night

Target opponent loses 3 life.
Flashback {5}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Restless Vents

This land enters tapped.
{T}: Add {B} or {R}.
{1}{B}{R}: Until end of turn, this land becomes a 2/3 black and red Insect creature with menace. It's still a land.
Whenever this land attacks, you may discard a card. If you do, draw a card.

Lightning Skelemental

Trample, haste
Whenever this creature deals combat damage to a player, that player discards two cards.
At the beginning of the end step, sacrifice this creature.

Hellspark Elemental

Trample, haste
At the beginning of the end step, sacrifice this creature.
Unearth {1}{R} ({1}{R}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Judith, the Scourge Diva

Other creatures you control get +1/+0.
Whenever a nontoken creature you control dies, Judith deals 1 damage to any target.

Mountain

Thunderkin Awakener

Haste
Whenever this creature attacks, choose target Elemental creature card in your graveyard with toughness less than this creature's toughness. Return that card to the battlefield tapped and attacking. Sacrifice it at the beginning of the next end step.

Dragonskull Summit

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

Blackcleave Cliffs

This land enters tapped unless you control two or fewer other lands.
{T}: Add {B} or {R}.

Dreadhorde Arcanist

Trample
Whenever this creature attacks, you may cast target instant or sorcery card with mana value less than or equal to this creature's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Swamp

Kroxa, Titan of Death's Hunger

When Kroxa enters, sacrifice it unless it escaped.
Whenever Kroxa enters or attacks, each opponent discards a card, then each opponent who didn't discard a nonland card this way loses 3 life.
Escape—{B}{B}{R}{R}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Spark Elemental

Trample, haste (This creature can deal excess combat damage to the player or planeswalker it's attacking. This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.

Vexing Devil

When this creature enters, any opponent may have it deal 4 damage to them. If a player does, sacrifice this creature.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Blood Crypt

({T}: Add {B} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.