Growing Dread

Flash
When Growing Dread enters, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
Whenever you turn a permanent face up, put a +1/+1 counter on it.

Oblivious Bookworm

At the beginning of your end step, you may draw a card. If you do, discard a card unless a permanent entered the battlefield face down under your control this turn or you turned a permanent face up this turn.

Under the Skin

Manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
You may return a permanent card from your graveyard to your hand.

Glitch Interpreter

When Glitch Interpreter enters, if you control no face-down permanents, return Glitch Interpreter to its owner's hand and manifest dread.
Whenever one or more colorless creatures you control deal combat damage to a player, draw a card.

Bashful Beastie

When Bashful Beastie dies, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Temur War Shaman

When Temur War Shaman enters, manifest the top card of your library. (Put that card 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.)
Whenever a permanent you control is turned face up, if it's a creature, you may have it fight target creature you don't control.

Forest

Manifest Dread

Manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Locus of Enlightenment

Locus of Enlightenment has each activated ability of the exiled cards used to craft it. You may activate each of those abilities only once each turn.
Whenever you activate an ability that isn't a mana ability, copy it. You may choose new targets for the copy.

The Enigma Jewel

The Enigma Jewel enters tapped.
{T}: Add {C}{C}. Spend this mana only to activate abilities.
Craft with four or more nonlands with activated abilities {8}{U} ({8}{U}, Exile this artifact, Exile the four or more from among other permanents you control and/or cards in your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

The Enigma Jewel // Locus of Enlightenment

Brine Elemental

Morph {5}{U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Brine Elemental is turned face up, each opponent skips their next untap step.

Stay Hidden, Stay Silent

Enchant creature
When Stay Hidden, Stay Silent enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.
{4}{U}{U}: Shuffle enchanted creature into its owner's library, then manifest dread. Activate only as a sorcery.

Become Anonymous

Exile target nontoken creature you own and the top two cards of your library in a face-down pile, shuffle that pile, then cloak those cards. They enter tapped. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)

Cursed Windbreaker

When Cursed Windbreaker enters, manifest dread, then attach Cursed Windbreaker to that creature. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
Equipped creature has flying.
Equip {3}

Write into Being

Look at the top two cards of your library. Manifest one of those cards, then put the other on the top or bottom of your library. (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.)

Threats Around Every Corner

When Threats Around Every Corner enters, manifest dread.
Whenever a face-down permanent you control enters, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Island

Defiant Survivor

Survival — At the beginning of your second main phase, if Defiant Survivor is tapped, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Conductive Machete

When Conductive Machete enters, manifest dread, then attach Conductive Machete to that creature. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
Equipped creature gets +2/+1.
Equip {4}

Obscuring Aether

Face-down creature spells you cast cost {1} less to cast.
{1}{G}: Turn Obscuring Aether face down. (It becomes a 2/2 creature.)

Twist Reality

Choose one —
• Counter target spell.
• Manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Scroll of Fate

{T}: Manifest a card from your hand. (Put that card 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.)

Ixidron

As Ixidron enters, turn all other nontoken creatures face down. (They're 2/2 creatures.)
Ixidron's power and toughness are each equal to the number of face-down creatures on the battlefield.

Valgavoth's Onslaught

Manifest dread X times, then put X +1/+1 counters on each of those creatures. (To manifest dread, look at the top two cards of your library, then put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Fear of Impostors

Flash
When Fear of Impostors enters, counter target spell. Its controller manifests dread. (That player looks at the top two cards of their library, then puts one onto the battlefield face down as a 2/2 creature and the other into their graveyard. If it's a creature card, it can be turned face up any time for its mana cost.)

Break Down the Door

Choose one —
• Exile target artifact.
• Exile target enchantment.
• Manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Primordial Mist

At the beginning of your end step, you may manifest the top card of your library. (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.)
Exile a face-down permanent you control face up: You may play that card this turn. (You still pay its costs. Timing rules still apply.)

Secret Plans

Face-down creatures you control get +0/+1.
Whenever a permanent you control is turned face up, draw a card.

Zimone, Mystery Unraveler

Landfall — Whenever a land you control enters, manifest dread if this is the first time this ability has resolved this turn. Otherwise, you may turn a permanent you control face up. (To manifest dread, look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

Ethereal Ambush

Manifest the top two cards of your library. (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.)

Curator Beastie

Reach
Colorless creatures you control enter with two additional +1/+1 counters on them.
Whenever Curator Beastie enters or attacks, manifest dread. (Look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)

The Foretold Soldier

The Foretold Soldier must be blocked if able.
The Foretold Soldier can't be blocked by more than one creature.
Whenever The Foretold Soldier deals damage, exile it face down. It becomes foretold.
Foretell {1}{G} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Paranormal Analyst

Whenever you manifest dread, put a card you put into your graveyard this way into your hand.

They Came from the Pipes

When They Came from the Pipes enters, manifest dread twice. (To manifest dread, look at the top two cards of your library. Put one onto the battlefield face down as a 2/2 creature and the other into your graveyard. Turn it face up any time for its mana cost if it's a creature card.)
Whenever a face-down creature you control enters, draw a card.

Ugin's Mastery

Whenever you cast a colorless creature spell, manifest the top card of your library. (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.)
Whenever you attack with creatures with total power 6 or greater, you may turn a face-down creature you control face up.

Formless Nurturing

Manifest the top card of your library, then put a +1/+1 counter on it. (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.)

Herdchaser Dragon

Flying, trample
Megamorph {5}{G}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its megamorph cost and put a +1/+1 counter on it.)
When Herdchaser Dragon is turned face up, put a +1/+1 counter on each other Dragon creature you control.

Dissection Tools

When Dissection Tools enters, manifest dread, then attach Dissection Tools to that creature.
Equipped creature gets +2/+2 and has deathtouch and lifelink.
Equip—Sacrifice a creature.