Conspiracy Theorist

Whenever Conspiracy Theorist attacks, you may pay {1} and discard a card. If you do, draw a card.
Whenever you discard one or more nonland cards, you may exile one of them from your graveyard. If you do, you may cast it this turn.

Bolas's Citadel

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library. If you cast a spell this way, pay life equal to its mana value rather than pay its mana cost.
{T}, Sacrifice ten nonland permanents: Each opponent loses 10 life.

Blood Crypt

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

Treasure Vault

{T}: Add {C}.
{X}{X}, {T}, Sacrifice Treasure Vault: Create X Treasure tokens.

Sulfurous Springs

{T}: Add {C}.
{T}: Add {B} or {R}. Sulfurous Springs deals 1 damage to you.

Luxury Suite

Luxury Suite enters tapped unless you have two or more opponents.
{T}: Add {B} or {R}.

Hellish Rebuke

Until end of turn, permanents your opponents control gain "When this permanent deals damage to the player who cast Hellish Rebuke, sacrifice this permanent. You lose 2 life."

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Inspiring Statuary

Nonartifact spells you cast have improvise. (Your artifacts can help cast those spells. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Valakut Exploration

Landfall — Whenever a land you control enters, exile the top card of your library. You may play that card for as long as it remains exiled.
At the beginning of your end step, if there are cards exiled with Valakut Exploration, put them into their owner's graveyard, then Valakut Exploration deals that much damage to each opponent.

Chandra, Torch of Defiance

+1: Exile the top card of your library. You may cast that card. If you don't, Chandra, Torch of Defiance deals 2 damage to each opponent.
+1: Add {R}{R}.
−3: Chandra, Torch of Defiance deals 4 damage to target creature.
−7: You get an emblem with "Whenever you cast a spell, this emblem deals 5 damage to any target."

Sensei's Divining Top

{1}: Look at the top three cards of your library, then put them back in any order.
{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Twinflame

Strive — This spell costs {2}{R} more to cast for each target beyond the first.
Choose any number of target creatures you control. For each of them, create a token that's a copy of that creature, except it has haste. Exile those tokens at the beginning of the next end step.