Watcher for Tomorrow

Hideaway 4 (When this creature enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
This creature enters tapped.
When this creature leaves the battlefield, put the exiled card into its owner's hand.

Meteor Golem

When this creature enters, destroy target nonland permanent an opponent controls.

Mistmeadow Witch

{2}{W}{U}: Exile target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Lembas

When this artifact enters, scry 1, then draw a card.
{2}, {T}, Sacrifice this artifact: You gain 3 life.
When this artifact is put into a graveyard from the battlefield, its owner shuffles it into their library.

Turn to Mist

Exile target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Azorius Charm

Choose one —
• Creatures you control gain lifelink until end of turn.
• Draw a card.
• Put target attacking or blocking creature on top of its owner's library.

Cataclysmic Gearhulk

Vigilance
When this creature enters, each player chooses an artifact, a creature, an enchantment, and a planeswalker from among the nonland permanents they control, then sacrifices the rest.

Reflector Mage

When this creature enters, return target creature an opponent controls to its owner's hand. That creature's owner can't cast spells with the same name as that creature until your next turn.

Soulherder

Whenever a creature is exiled from the battlefield, put a +1/+1 counter on this creature.
At the beginning of your end step, you may exile another target creature you control, then return that card to the battlefield under its owner's control.

Treasure Mage

When this creature enters, you may search your library for an artifact card with mana value 6 or greater, reveal it, put it into your hand, then shuffle.

Bladewheel Chariot

Tap two other untapped artifacts you control: This Vehicle becomes an artifact creature until end of turn.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

Spring-Loaded Sawblades

Flash
When this artifact enters, it deals 5 damage to target tapped creature an opponent controls.
Craft with artifact {3}{W} ({3}{W}, Exile this artifact, Exile another artifact you control or an artifact card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Spring-Loaded Sawblades // Bladewheel Chariot

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Etherium Sculptor

Artifact spells you cast cost {1} less to cast.

War Priest of Thune

When this creature enters, you may destroy target enchantment.

Meteorite

When this artifact enters, it deals 2 damage to any target.
{T}: Add one mana of any color.

Lena, Selfless Champion

When Lena enters, create a 1/1 white Soldier creature token for each nontoken creature you control.
Sacrifice Lena: Creatures you control with power less than Lena's power gain indestructible until end of turn.

Cloud Key

As this artifact enters, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Aven Surveyor

Flying
When this creature enters, choose one —
• Put a +1/+1 counter on this creature.
• Return target creature to its owner's hand.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Unctus, Grand Metatect

Other blue creatures you control have "Whenever this creature becomes tapped, draw a card, then discard a card."
Other artifact creatures you control get +1/+1.
{U/P}: Until end of turn, target creature you control becomes a blue artifact in addition to its other colors and types. Activate only as a sorcery. ({U/P} can be paid with either {U} or 2 life.)

Ecologist's Terrarium

When this artifact enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.
{2}, {T}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.

Proud Pack-Rhino

When this creature enters, choose one —
• Put a shield counter on target permanent. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Eriette's Tempting Apple

When Eriette's Tempting Apple enters, gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn.
{2}, {T}, Sacrifice Eriette's Tempting Apple: You gain 3 life.
{2}, {T}, Sacrifice Eriette's Tempting Apple: Target opponent loses 3 life.

Soul-Guide Lantern

When this artifact enters, exile target card from a graveyard.
{T}, Sacrifice this artifact: Exile each opponent's graveyard.
{1}, {T}, Sacrifice this artifact: Draw a card.

Golden Egg

When this artifact enters, draw a card.
{1}, {T}, Sacrifice this artifact: Add one mana of any color.
{2}, {T}, Sacrifice this artifact: You gain 3 life.

Priest of Ancient Lore

When this creature enters, you gain 1 life and draw a card.

Rise and Shine

Target noncreature artifact you control becomes a 0/0 artifact creature. Put four +1/+1 counters on each artifact that became a creature this way.
Overload {4}{U}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Master Splicer

When this creature enters, create a 3/3 colorless Phyrexian Golem artifact creature token.
Golems you control get +1/+1.

Prophetic Prism

When this artifact enters, draw a card.
{1}, {T}: Add one mana of any color.

Sensor Splicer

When this creature enters, create a 3/3 colorless Phyrexian Golem artifact creature token.
Golem creatures you control have vigilance.

Cloudkin Seer

Flying
When this creature enters, draw a card.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Yorion, Sky Nomad

Companion — Your starting deck contains at least twenty cards more than the minimum deck size. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Flying
When Yorion enters, exile any number of other nonland permanents you own and control. Return those cards to the battlefield at the beginning of the next end step.

Semester's End

Exile any number of target creatures and/or planeswalkers you control. At the beginning of the next end step, return each of them to the battlefield under its owner's control. Each of them enters with an additional +1/+1 counter on it if it's a creature and an additional loyalty counter on it if it's a planeswalker.

Master's Manufactory

{T}: Create a 4/4 white and blue Golem artifact creature token. Activate only if this artifact or another artifact entered the battlefield under your control this turn.

Master's Guide-Mural

When this artifact enters, create a 4/4 white and blue Golem artifact creature token.
Craft with artifact {4}{W}{W}{U} ({4}{W}{W}{U}, Exile this artifact, Exile another artifact you control or an artifact card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Master's Guide-Mural // Master's Manufactory

Peregrine Drake

Flying
When this creature enters, untap up to five lands.

Gold Pan

When this Equipment enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Equipped creature gets +1/+1.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Skyscanner

Thought Monitor

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When this creature enters, draw two cards.

The One Ring

Indestructible
When The One Ring enters, if you cast it, you gain protection from everything until your next turn.
At the beginning of your upkeep, you lose 1 life for each burden counter on The One Ring.
{T}: Put a burden counter on The One Ring, then draw a card for each burden counter on The One Ring.

Archaeomender

When this creature enters, return target artifact card from your graveyard to your hand.

Thought Prison

Imprint — When this artifact enters, you may have target player reveal their hand. If you do, choose a nonland card from it and exile that card.
Whenever a player casts a spell that shares a color or mana value with the exiled card, this artifact deals 2 damage to that player.

Guild Globe

When this artifact enters, draw a card.
{2}, {T}, Sacrifice this artifact: Add two mana of different colors.

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Cloudblazer

Flying
When this creature enters, you gain 2 life and draw two cards.

Skyclave Apparition

When this creature enters, exile up to one target nonland, nontoken permanent you don't control with mana value 4 or less.
When this creature leaves the battlefield, the exiled card's owner creates an X/X blue Illusion creature token, where X is the mana value of the exiled card.

Blade Splicer

When this creature enters, create a 3/3 colorless Phyrexian Golem artifact creature token.
Golems you control have first strike.

Flickerwisp

Flying
When this creature enters, exile another target permanent. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Arcanist's Owl

Flying
When this creature enters, look at the top four cards of your library. You may reveal an artifact or enchantment card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Tribute Mage

When this creature enters, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.

Torrential Gearhulk

Flash
When this creature enters, you may cast target instant card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Wing Splicer

When this creature enters, create a 3/3 colorless Phyrexian Golem artifact creature token.
Golem creatures you control have flying.

Skyclave Relic

Kicker {3}
Indestructible
When this artifact enters, if it was kicked, create two tapped tokens that are copies of this artifact.
{T}: Add one mana of any color.

Akal Pakal, First Among Equals

At the beginning of each player's end step, if an artifact entered the battlefield under your control this turn, look at the top two cards of your library. Put one of them into your hand and the other into your graveyard.

Tishana's Tidebinder

Flash
When this creature enters, counter up to one target activated or triggered ability. If an ability of an artifact, creature, or planeswalker is countered this way, that permanent loses all abilities for as long as this creature remains on the battlefield. (Mana abilities can't be targeted.)

Scampering Surveyor

When this creature enters, search your library for a basic land card or Cave card, put it onto the battlefield tapped, then shuffle.

Dauntless Dismantler

Artifacts your opponents control enter tapped.
{X}{X}{W}, Sacrifice this creature: Destroy each artifact with mana value X.

Runaway Boulder

Flash
When this artifact enters, it deals 6 damage to target creature an opponent controls.
Cycling {2} ({2}, Discard this card: Draw a card.)

Eerie Interlude

Exile any number of target creatures you control. Return those cards to the battlefield under their owner's control at the beginning of the next end step.

Foundry Inspector

Abuelo, Ancestral Echo

Flying, ward {2}
{1}{W}{U}: Exile another target creature or artifact you control. Return it to the battlefield under its owner's control at the beginning of the next end step.

Evangel of Heliod

When this creature enters, create a number of 1/1 white Soldier creature tokens equal to your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)

Rustspore Ram

When this creature enters, destroy target Equipment.

Springjack Shepherd

Chroma — When this creature enters, create a 0/1 white Goat creature token for each white mana symbol in the mana costs of permanents you control.

Guidestone Compass

{1}, {T}: Target creature you control explores. Activate only as a sorcery. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on that creature, then put the card back or put it into your graveyard.)

Lodestone Needle

Flash
When this artifact enters, tap up to one target artifact or creature and put two stun counters on it.
Craft with artifact {2}{U} ({2}{U}, Exile this artifact, Exile another artifact you control or an artifact card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Lodestone Needle // Guidestone Compass

Deceiver Exarch

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, choose one —
• Untap target permanent you control.
• Tap target permanent an opponent controls.

Elesh Norn, Mother of Machines

Vigilance
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Permanents entering don't cause abilities of permanents your opponents control to trigger.