Kadena, Slinking Sorcerer

The first face-down creature spell you cast each turn costs {3} less to cast.
Whenever a face-down creature you control enters, draw a card.

Ugin, the Ineffable

Colorless spells you cast cost {2} less to cast.
+1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand.
−3: Destroy target permanent that's one or more colors.

Mighty Servant of Leuk-o

Trample
Ward—Discard a card.
Whenever this Vehicle becomes crewed for the first time each turn, if it was crewed by exactly two creatures, it gains "Whenever this creature deals combat damage to a player, draw two cards" until end of turn.
Crew 4

Vesuvan Shapeshifter

As this creature enters or is turned face up, you may choose another creature on the battlefield. If you do, until this creature is turned face down, it becomes a copy of that creature, except it has "At the beginning of your upkeep, you may turn this creature face down."
Morph {1}{U}

Army of the Damned

Create thirteen tapped 2/2 black Zombie creature tokens.
Flashback {7}{B}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Duskana, the Rage Mother

When Duskana enters, draw a card for each creature you control with base power and toughness 2/2.
Whenever a creature you control with base power and toughness 2/2 attacks, it gets +3/+3 until end of turn.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Garth One-Eye

{T}: Choose a card name that hasn't been chosen from among Disenchant, Braingeyser, Terror, Shivan Dragon, Regrowth, and Black Lotus. Create a copy of the card with the chosen name. You may cast the copy. (You still pay its costs.)

Assassin's Trophy

Destroy target permanent an opponent controls. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Open the Gates

Search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Gift of Doom

Enchant creature
Enchanted creature has deathtouch and indestructible.
Morph—Sacrifice another creature. (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
As this Aura is turned face up, you may attach it to a creature.

Forest

Rattleclaw Mystic

{T}: Add {G}, {U}, or {R}.
Morph {2} (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 this creature is turned face up, add {G}{U}{R}.

Sagu Mauler

Trample, hexproof
Morph {3}{G}{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.)

Roshan, Hidden Magister

Other creatures you control are Assassins in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
Face-down creatures you control have menace.
Whenever a permanent you control is turned face up, you draw a card and you lose 1 life.

Jeering Instigator

Morph {2}{R} (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 this creature is turned face up, if it's your turn, gain control of another target creature until end of turn. Untap that creature. It gains haste until end of turn.

Gilded Lotus

Gateway Plaza

This land enters tapped.
When this land enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Simic Signet

Cliffgate

This land enters tapped.
As this land enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Bane of the Living

Morph {X}{B}{B} (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 this creature is turned face up, all creatures get -X/-X until end of turn.

Ezuri's Predation

For each creature your opponents control, create a 4/4 green Phyrexian Beast creature token. Each of those tokens fights a different one of those creatures.

Terror of the Peaks

Flying
Spells your opponents cast that target this creature cost an additional 3 life to cast.
Whenever another creature you control enters, this creature deals damage equal to that creature's power to any target.

True Identity

Whenever this enchantment or another permanent you control is turned face up, scry 1, then draw a card. This ability triggers only once each turn.
Disguise {W} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

Yargle and Multani

Simic Guildgate

This land enters tapped.
{T}: Add {G} or {U}.

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.)

Explosive Vegetation

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Yarus, Roar of the Old Gods

Other creatures you control have haste.
Whenever one or more face-down creatures you control deal combat damage to a player, draw a card.
Whenever a face-down creature you control dies, return it to the battlefield face down under its owner's control if it's a permanent card, then turn it face up.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Swamp

Welcoming Vampire

Flying
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.

Kaust, Eyes of the Glade

Whenever a creature you control that was turned face up this turn deals combat damage to a player, draw a card.
{T}: Turn target face-down attacking creature you control face up.

Dimir Guildgate

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

Icefeather Aven

Flying
Morph {1}{G}{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 this creature is turned face up, you may return another target creature to its owner's hand.

Rite of Replication

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Necromancer's Covenant

When this enchantment enters, exile all creature cards from target player's graveyard, then create a 2/2 black Zombie creature token for each card exiled this way.
Zombies you control have lifelink.

Rakish Scoundrel

Deathtouch
When this creature enters or is turned face up, target creature gains indestructible until end of turn.
Disguise {4}{B/G}{B/G} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

Beseech the Queen

({2/B} can be paid with any two mana or with {B}. This card's mana value is 6.)
Search your library for a card with mana value less than or equal to the number of lands you control, reveal it, put it into your hand, then shuffle.

Evacuation

Return all creatures to their owners' hands.

Willing

Creatures you control gain deathtouch and lifelink until end of turn.
Fuse (You may cast one or both halves of this card from your hand.)

Ready

Creatures you control gain indestructible until end of turn. Untap each creature you control.
Fuse (You may cast one or both halves of this card from your hand.)

Ready // Willing

Navigation Orb

{2}, {T}, Sacrifice this artifact: Search your library for up to two basic land cards and/or Gate cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Selesnya Guildgate

This land enters tapped.
{T}: Add {G} or {W}.

Etrata, Deadly Fugitive

Deathtouch
Face-down creatures you control have "{2}{U}{B}: Turn this creature face up. If you can't, exile it, then you may cast the exiled card without paying its mana cost."
Whenever an Assassin you control deals combat damage to an opponent, cloak the top card of that player's library.

Elas il-Kor, Sadistic Pilgrim

Deathtouch
Whenever another creature you control enters, you gain 1 life.
Whenever another creature you control dies, each opponent loses 1 life.

Terminate

Destroy target creature. It can't be regenerated.

Sol Ring

Golgari Rot Farm

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {B}{G}.

Gond Gate

Gates you control enter untapped.
{T}: Add {C}.
{T}: Add one mana of any color that a Gate you control could produce.

Corpse Knight

Whenever another creature you control enters, each opponent loses 1 life.

Boros Guildgate

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

Obscura Storefront

When this land enters, sacrifice it. When you do, search your library for a basic Plains, Island, or Swamp card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Basilisk Gate

{T}: Add {C}.
{2}, {T}: Target creature gets +X/+X until end of turn, where X is the number of Gates you control. Activate only as a sorcery.

Meddling Mage

As this creature enters, choose a nonland card name.
Spells with the chosen name can't be cast.

Exit Specialist

This creature can't be blocked by creatures with power 3 or greater.
Disguise {1}{U} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When this creature is turned face up, return another target creature to its owner's hand.

Biomass Mutation

Creatures you control have base power and toughness X/X until end of turn.

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.

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Hunter's Insight

Choose target creature you control. Whenever that creature deals combat damage to a player or planeswalker this turn, draw that many cards.

Island

Kadena's Silencer

When Kadena's Silencer is turned face up, counter all abilities your opponents control.
Megamorph {1}{U} (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.)

Golgari Guildgate

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

Incongruity

Exile target creature. That creature's controller creates a 3/3 green Frog Lizard creature token.

Incubation

Look at the top five cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Incubation // Incongruity

Storm Herd

Create X 1/1 white Pegasus creature tokens with flying, where X is your life total.

Wispdrinker Vampire

Flying
Whenever another creature you control with power 2 or less enters, each opponent loses 1 life and you gain 1 life.
{5}{W}{B}: Creatures you control with power 2 or less gain deathtouch and lifelink until end of turn.

Orzhov Guildgate

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

Plains

Restless Vents

This land enters tapped.
{T}: Add {B} or {R}.
{1}{B}{R}: Until end of turn, this land becomes a 2/3 black and red Insect creature with menace. It's still a land.
Whenever this land attacks, you may discard a card. If you do, draw a card.

Baldur's Gate

{T}: Add {C}.
{2}, {T}: Add X mana of any one color, where X is the number of other Gates you control.

Molten Gatekeeper

Whenever another creature you control enters, this creature deals 1 damage to each opponent.
Unearth {R} ({R}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Case of the Shattered Pact

When this Case enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
To solve — There are five colors among permanents you control. (If unsolved, solve at the beginning of your end step.)
Solved — At the beginning of combat on your turn, target creature you control gains flying, double strike, and vigilance until end of turn.

Kheru Spellsnatcher

Morph {4}{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 this creature is turned face up, counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard. You may cast that card without paying its mana cost for as long as it remains exiled.

Hide in Plain Sight

Look at the top five cards of your library, cloak two of them, and put the rest on the bottom of your library in a random order. (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.)

Hooded Hydra

This creature enters with X +1/+1 counters on it.
When this creature dies, create a 1/1 green Snake creature token for each +1/+1 counter on it.
Morph {3}{G}{G}
As this creature is turned face up, put five +1/+1 counters on it.

Panoptic Projektor

{T}: The next face-down creature spell you cast this turn costs {3} less to cast.
If turning a face-down permanent face up causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Thelonite Hermit

All Saprolings get +1/+1.
Morph {3}{G}{G} (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 this creature is turned face up, create four 1/1 green Saproling creature tokens.

Dimir Aqueduct

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{B}.

Thousand Winds

Flying
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 this creature is turned face up, return all other tapped creatures to their owners' hands.

Trail of Mystery

Whenever a face-down creature you control enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Whenever a permanent you control is turned face up, if it's a creature, it gets +2/+2 until end of turn.

Azorius Guildgate

This land enters tapped.
{T}: Add {W} or {U}.

Warleader's Call

Creatures you control get +1/+1.
Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Mountain

March of Otherworldly Light

As an additional cost to cast this spell, you may exile any number of white cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Exile target artifact, creature, or enchantment with mana value X or less.

Experiment Twelve

Trample
Whenever this creature or another creature you control is turned face up, put +1/+1 counters on that creature equal to its power.
Disguise {4}{G} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

Hidden Dragonslayer

Lifelink
Megamorph {2}{W} (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 this creature is turned face up, destroy target creature with power 4 or greater an opponent controls.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Rakdos Guildgate

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

Manor Gate

This land enters tapped.
As this land enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Den Protector

Creatures with power less than this creature's power can't block it.
Megamorph {1}{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 this creature is turned face up, return target card from your graveyard to your hand.

Graven Cairns

{T}: Add {C}.
{B/R}, {T}: Add {B}{B}, {B}{R}, or {R}{R}.

Command Tower

Gruul Turf

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {R}{G}.