Cinder Barrens

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

Goblin Firebug

When Goblin Firebug leaves the battlefield, sacrifice a land.

Glorious End

End the turn. (Exile all spells and abilities from the stack, including this card. The player whose turn it is discards down to their maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)
At the beginning of your next end step, you lose the game.

Juju Bubble

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
When you play a card, sacrifice Juju Bubble.
{2}: You gain 1 life.

Rakdos Guildgate

This land enters tapped.
{T}: Add {B} or {R}.

Enslaved Horror

When Enslaved Horror enters, each other player may return a creature card from their graveyard to the battlefield.

Kamahl's Sledge

Kamahl's Sledge deals 4 damage to target creature.
Threshold — If seven or more cards are in your graveyard, instead Kamahl's Sledge deals 4 damage to that creature and 4 damage to that creature's controller.

Pain's Reward

Each player may bid life. You start the bidding with a bid of any number. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid and draws four cards.

Seismic Rupture

Seismic Rupture deals 2 damage to each creature without flying.

Shinka Gatekeeper

Whenever Shinka Gatekeeper is dealt damage, it deals that much damage to you.

Jangling Automaton

Whenever Jangling Automaton attacks, untap all creatures defending player controls.

Grollub

Whenever Grollub is dealt damage, each opponent gains that much life.

Mountain

Rolling Temblor

Rolling Temblor deals 2 damage to each creature without flying.
Flashback {4}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Obelisk of Undoing

{6}, {T}: Return target permanent you both own and control to your hand.

Mindless Null

Mindless Null can't block unless you control a Vampire.

Swamp

Abyssal Persecutor

Flying, trample
You can't win the game and your opponents can't lose the game.

Pain Seer

Inspired — Whenever Pain Seer becomes untapped, reveal the top card of your library and put that card into your hand. You lose life equal to that card's mana value.