The Dominion Bracelet

Equipped creature gets +1/+1 and has "{15}, Exile The Dominion Bracelet: You control target opponent during their next turn. This ability costs {X} less to activate, where X is this creature's power. Activate only as a sorcery." (You see all cards that player could see and make all decisions for them.)
Equip {1}

Flayer of Loyalties

When you cast this spell, gain control of target creature until end of turn. Untap that creature. Until end of turn, it has base power and toughness 10/10 and gains trample, annihilator 2, and haste.
Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents of their choice.)
Trample

Whispers of Emrakul

Target opponent discards a card at random.
Delirium — If there are four or more card types among cards in your graveyard, that player discards two cards at random instead.

Herigast, Erupting Nullkite

Emerge {6}{R}{R} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, you may exile your hand. If you do, draw three cards.
Flying
Each creature spell you cast has emerge. The emerge cost is equal to its mana cost.

Skittering Precursor

Devoid (This card has no color.)
Menace
Whenever you sacrifice a nontoken permanent, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."

Abolisher of Bloodlines

Flying
When this creature transforms into Abolisher of Bloodlines, target opponent sacrifices three creatures of their choice.

Voldaren Pariah

Flying
Sacrifice three other creatures: Transform this creature.
Madness {B}{B}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Voldaren Pariah // Abolisher of Bloodlines

Evelyn, the Covetous

Flash
Whenever Evelyn or another Vampire you control enters, exile the top card of each player's library with a collection counter on it.
Once each turn, you may play a card from exile with a collection counter on it if it was exiled by an ability you controlled, and you may spend mana as though it were mana of any color to cast it.

Deadly Embrace

Destroy target creature an opponent controls. Then draw a card for each creature that died this turn.

Syphon Essence

Counter target creature or planeswalker spell. Create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")

Aurora of Emrakul

Flying, deathtouch
Whenever this creature attacks, each opponent loses 3 life.

Cryptolith Fragment

This artifact enters tapped.
{T}: Add one mana of any color. Each player loses 1 life.
At the beginning of your upkeep, if each player has 10 or less life, transform this artifact.

Cryptolith Fragment // Aurora of Emrakul

Stromkirk Occultist

Trample
Whenever this creature deals combat damage to a player, exile the top card of your library. Until end of turn, you may play that card.
Madness {1}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Voidpouncer

Devoid (This card has no color.)
Kicker {2}{C} (You may pay an additional {2}{C} as you cast this spell.)
If this creature was kicked, it enters with two +1/+1 counters and a trample counter on it and with haste.

Bloodcrazed Socialite

Menace
When this creature enters, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")
Whenever this creature attacks, you may sacrifice a Blood token. If you do, it gets +2/+2 until end of turn.

Blood Petal Celebrant

This creature has first strike as long as it's attacking.
When this creature dies, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")

Corrupted Shapeshifter

Devoid (This card has no color.)
As this creature enters, it becomes your choice of a 3/3 creature with flying, a 2/5 creature with vigilance, or a 0/12 creature with defender.

Lacerate Flesh

Lacerate Flesh deals 4 damage to target creature. Create a number of Blood tokens equal to the amount of excess damage dealt to that creature this way. (They're artifacts with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")

Falkenrath Celebrants

Menace (This creature can't be blocked except by two or more creatures.)
When this creature enters, create two Blood tokens. (They're artifacts with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")

Belligerent Guest

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Whenever this creature deals combat damage to a player, create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")

Bloody Betrayal

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. Create a Blood token. (It's an artifact with "{1}, {T}, Discard a card, Sacrifice this token: Draw a card.")

Emrakul's Messenger

Devoid (This card has no color.)
Flying
Whenever you draw your second card each turn, create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this token: Add {C}."

Spawn-Gang Commander

Devoid (This card has no color.)
When you cast this spell, create three 0/1 colorless Eldrazi Spawn creature tokens with "Sacrifice this token: Add {C}."
{1}{C}, Sacrifice an Eldrazi: This creature deals 2 damage to any target.

Emrakul, the Promised End

This spell costs {1} less to cast for each card type among cards in your graveyard.
When you cast this spell, you gain control of target opponent during that player's next turn. After that turn, that player takes an extra turn.
Flying, trample, protection from instants