It That Betrays

Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents of their choice.)
Whenever an opponent sacrifices a nontoken permanent, put that card onto the battlefield under your control.

Gisela, the Broken Blade

Flying, first strike, lifelink
At the beginning of your end step, if you both own and control Gisela and a creature named Bruna, the Fading Light, exile them, then meld them into Brisela, Voice of Nightmares.

Ulamog, the Ceaseless Hunger

When you cast this spell, exile two target permanents.
Indestructible
Whenever Ulamog attacks, defending player exiles the top twenty cards of their library.

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

Ulalek, Fused Atrocity

Devoid (This card has no color.)
Whenever you cast an Eldrazi spell, you may pay {C}{C}. If you do, copy all spells you control, then copy all other activated and triggered abilities you control. You may choose new targets for the copies. (Mana abilities can't be copied.)

Ulamog's Dreadsire

Vigilance
Ward—Sacrifice a permanent with mana value 1 or greater.
{T}: Create a 10/10 colorless Eldrazi creature token.

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

Spawnsire of Ulamog

Annihilator 1 (Whenever this creature attacks, defending player sacrifices a permanent of their choice.)
{4}: Create two 0/1 colorless Eldrazi Spawn creature tokens. They have "Sacrifice this token: Add {C}."
{20}: Cast any number of Eldrazi spells from among cards you own outside the game without paying their mana costs.

Pathrazer of Ulamog

Annihilator 3 (Whenever this creature attacks, defending player sacrifices three permanents of their choice.)
This creature can't be blocked except by three or more creatures.

Kozilek, the Great Distortion

When you cast this spell, if you have fewer than seven cards in hand, draw cards equal to the difference.
Menace
Discard a card with mana value X: Counter target spell with mana value X.

Devourer of Destiny

You may reveal this card from your opening hand. If you do, at the beginning of your first upkeep, look at the top four cards of your library. You may put one of those cards back on top of your library. Exile the rest.
When you cast this spell, exile target permanent that's one or more colors.

Echoes of Eternity

If a triggered ability of a colorless spell you control or another colorless permanent you control triggers, that ability triggers an additional time.
Whenever you cast a colorless spell, copy it. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Eldrazi Temple

{T}: Add {C}.
{T}: Add {C}{C}. Spend this mana only to cast colorless Eldrazi spells or activate abilities of colorless Eldrazi.

Ulamog, the Defiler

When you cast this spell, target opponent exiles the top half of their library, rounded up.
Ward—Sacrifice two permanents.
Ulamog enters with a number of +1/+1 counters on it equal to the greatest mana value among cards in exile.
Ulamog has annihilator X, where X is the number of +1/+1 counters on it.

Void Winnower

Your opponents can't cast spells with even mana values. (Zero is even.)
Your opponents can't block with creatures with even mana values.

Eldrazi Mimic

Whenever another colorless creature you control enters, you may change this creature's base power and toughness to that creature's power and toughness until end of turn.

Emrakul, the World Anew

When you cast this spell, gain control of all creatures target player controls.
Flying, protection from spells and from permanents that were cast this turn
When Emrakul leaves the battlefield, sacrifice all creatures you control.
Madness—Pay six {C}.

All Is Dust

Each player sacrifices all permanents they control that are one or more colors.

Bruna, the Fading Light

When you cast this spell, you may return target Angel or Human creature card from your graveyard to the battlefield.
Flying, vigilance
(Melds with Gisela, the Broken Blade.)

Reality Smasher

({C} represents colorless mana.)
Trample, haste
Whenever this creature becomes the target of a spell an opponent controls, counter that spell unless its controller discards a card.

Desolation Twin

When you cast this spell, create a 10/10 colorless Eldrazi creature token.

Hanweir Garrison

Whenever this creature attacks, create two 1/1 red Human creature tokens that are tapped and attacking.
(Melds with Hanweir Battlements.)

Kozilek's Command

Choose two —
• Target player creates X 0/1 colorless Eldrazi Spawn creature tokens with "Sacrifice this creature: Add {C}."
• Target player scries X, then draws a card.
• Exile target creature with mana value X or less.
• Exile up to X target cards from graveyards.

Hanweir Battlements

{T}: Add {C}.
{R}, {T}: Target creature gains haste until end of turn.
{3}{R}{R}, {T}: If you both own and control this land and a creature named Hanweir Garrison, exile them, then meld them into Hanweir, the Writhing Township.

Conduit of Ruin

When you cast this spell, you may search your library for a colorless creature card with mana value 7 or greater, reveal it, then shuffle and put that card on top.
The first creature spell you cast each turn costs {2} less to cast.

Not of This World

Counter target spell or ability that targets a permanent you control.
This spell costs {7} less to cast if it targets a spell or ability that targets a creature you control with power 7 or greater.

Eldritch Immunity

Target creature you control gains protection from each color until end of turn.
Overload {4}{C} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Mishra's Workshop

{T}: Add {C}{C}{C}. Spend this mana only to cast artifact spells.

Spawnbed Protector

At the beginning of your end step, return up to one target Eldrazi creature card from your graveyard to your hand. Create two 1/1 colorless Eldrazi Scion creature tokens with "Sacrifice this token: Add {C}."

Endless One

This creature enters with X +1/+1 counters on it.

Eternal Scourge

You may cast this card from exile.
When this creature becomes the target of a spell or ability an opponent controls, exile this creature.

The Tabernacle at Pendrell Vale

All creatures have "At the beginning of your upkeep, destroy this creature unless you pay {1}."

Zhulodok, Void Gorger

Colorless spells you cast from your hand with mana value 7 or greater have "Cascade, cascade." (When you cast one, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order. Then do it again.)

Thought-Knot Seer

({C} represents colorless mana.)
When this creature enters, target opponent reveals their hand. You choose a nonland card from it and exile that card.
When this creature leaves the battlefield, target opponent draws a card.

Eldrazi Conscription

Enchant creature
Enchanted creature gets +10/+10 and has trample and annihilator 2. (Whenever it attacks, defending player sacrifices two permanents of their choice.)

Kozilek, the Broken Reality

When you cast this spell, up to two target players each manifest two cards from their hands. For each card manifested this way, you draw a card. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)
Other colorless creatures you control get +3/+2.

Ulamog, the Infinite Gyre

When you cast this spell, destroy target permanent.
Indestructible
Annihilator 4 (Whenever this creature attacks, defending player sacrifices four permanents of their choice.)
When Ulamog is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.

Kozilek, Butcher of Truth

When you cast this spell, draw four cards.
Annihilator 4 (Whenever this creature attacks, defending player sacrifices four permanents of their choice.)
When Kozilek is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.