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.

Prairie Stream

({T}: Add {W} or {U}.)
This land enters tapped unless you control two or more basic lands.

Island

Lavinia of the Tenth

Protection from red
When Lavinia enters, detain each nonland permanent your opponents control with mana value 4 or less. (Until your next turn, those permanents can't attack or block and their activated abilities can't be activated.)

Muddle the Mixture

Counter target instant or sorcery spell.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Ephara, God of the Polis

Indestructible
As long as your devotion to white and blue is less than seven, Ephara isn't a creature.
At the beginning of each upkeep, if you had another creature enter the battlefield under your control last turn, draw a card.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Mystic Gate

{T}: Add {C}.
{W/U}, {T}: Add {W}{W}, {W}{U}, or {U}{U}.

Dovin's Acuity

When this enchantment enters, you gain 2 life and draw a card.
Whenever you cast an instant spell during your main phase, you may return this enchantment to its owner's hand.

Cloud of Faeries

Flying
When this creature enters, untap up to two lands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Plains

Ichor Wellspring

When this artifact enters or is put into a graveyard from the battlefield, draw a card.

Dissipate

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Negate

War Priest of Thune

When this creature enters, you may destroy target enchantment.

Faith's Fetters

Enchant permanent
When this Aura enters, you gain 4 life.
Enchanted permanent can't attack or block, and its activated abilities can't be activated unless they're mana abilities.

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.

Peregrine Drake

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

Mirrormade

You may have this enchantment enter as a copy of any artifact or enchantment on the battlefield.

Elite Guardmage

Flying
When this creature enters, you gain 3 life and draw a card.

Mycosynth Wellspring

When this artifact enters or is put into a graveyard from the battlefield, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Time Wipe

Return a creature you control to its owner's hand, then destroy all creatures.

Archaeomancer

When this creature enters, return target instant or sorcery card from your graveyard to your hand.

Unquestioned Authority

Enchant creature
When this Aura enters, draw a card.
Enchanted creature has protection from creatures.

Counterspell

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Nevermaker

Flying
When this creature leaves the battlefield, put target nonland permanent on top of its owner's library.
Evoke {3}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Mulldrifter

Flying
When this creature enters, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)

Glen Elendra Archmage

Flying
{U}, Sacrifice this creature: Counter target noncreature spell.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Trial of Knowledge

When this enchantment enters, draw three cards, then discard a card.
When a Cartouche you control enters, return this enchantment to its owner's hand.

Sunblast Angel

Flying
When this creature enters, destroy all tapped creatures.

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.

Port Town

As this land enters, you may reveal a Plains or Island card from your hand. If you don't, this land enters tapped.
{T}: Add {W} or {U}.

Omen of the Sun

Flash
When this enchantment enters, create two 1/1 white Human Soldier creature tokens and you gain 2 life.
{2}{W}, Sacrifice this enchantment: Scry 2.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Render Silent

Counter target spell. Its controller can't cast spells this turn.

Spine of Ish Sah

When this artifact enters, destroy target permanent.
When this artifact is put into a graveyard from the battlefield, return it to its owner's hand.

Agent of Treachery

When this creature enters, gain control of target permanent.
At the beginning of your end step, if you control three or more permanents you don't own, draw three cards.

Irrigated Farmland

({T}: Add {W} or {U}.)
This land enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Geist-Honored Monk

Vigilance
Geist-Honored Monk's power and toughness are each equal to the number of creatures you control.
When this creature enters, create two 1/1 white Spirit creature tokens with flying.

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.

Sea Gate Oracle

When this creature enters, look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.

Disdainful Stroke

Counter target spell with mana value 4 or greater.

Sea of Clouds

This land enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Mnemonic Wall

Defender
When this creature enters, you may return target instant or sorcery card from your graveyard to your hand.

Rishadan Cutpurse

When this creature enters, each opponent sacrifices a permanent of their choice unless they pay {1}.

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Kiora Bests the Sea God

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create an 8/8 blue Kraken creature token with hexproof.
II — Tap all nonland permanents target opponent controls. They don't untap during their controller's next untap step.
III — Gain control of target permanent an opponent controls. Untap it.

Venser, Shaper Savant

Flash (You may cast this spell any time you could cast an instant.)
When Venser enters, return target spell or permanent to its owner's hand.

Reality Acid

Enchant permanent
Vanishing 3 (This Aura enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When this Aura leaves the battlefield, enchanted permanent's controller sacrifices it.

Command Tower

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

Omen of the Sea

Flash (You may cast this spell any time you could cast an instant.)
When this enchantment enters, scry 2, then draw a card.
{2}{U}, Sacrifice this enchantment: Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Grand Arbiter Augustin IV

White spells you cast cost {1} less to cast.
Blue spells you cast cost {1} less to cast.
Spells your opponents cast cost {1} more to cast.

Brago, King Eternal

Flying
Whenever Brago deals combat damage to a player, exile any number of target nonland permanents you control, then return those cards to the battlefield under their owner's control.

Hour of Revelation

This spell costs {3} less to cast if there are ten or more nonland permanents on the battlefield.
Destroy all nonland permanents.

Heliod's Intervention

Choose one —
• Destroy X target artifacts and/or enchantments.
• Target player gains twice X life.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Whirler Rogue

When this creature enters, create two 1/1 colorless Thopter artifact creature tokens with flying.
Tap two untapped artifacts you control: Target creature can't be blocked this turn.

Glacial Fortress

This land enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Temple of Enlightenment

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {W} or {U}.

Rest in Peace

When this enchantment enters, exile all graveyards.
If a card or token would be put into a graveyard from anywhere, exile it instead.

Dawn

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Return all creature cards with power 2 or less from your graveyard to your hand.

Dusk

Destroy all creatures with power 3 or greater.

Dusk // Dawn

Wall of Omens

Defender
When this creature enters, draw a card.

Teferi's Time Twist

Exile target permanent you control. Return that card to the battlefield under its owner's control at the beginning of the next end step. If it enters as a creature, it enters with an additional +1/+1 counter on it.

Azor, the Lawbringer

Flying
When Azor enters, each opponent can't cast instant or sorcery spells during that player's next turn.
Whenever Azor attacks, you may pay {X}{W}{U}{U}. If you do, you gain X life and draw X cards.

Phyrexian Ingester

Imprint — When this creature enters, you may exile target nontoken creature.
This creature gets +X/+Y, where X is the exiled creature card's power and Y is its toughness.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Nimbus Maze

{T}: Add {C}.
{T}: Add {W}. Activate only if you control an Island.
{T}: Add {U}. Activate only if you control a Plains.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Myr Battlesphere

When this creature enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever this creature attacks, you may tap X untapped Myr you control. If you do, this creature gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

Cloudblazer

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

Curator's Ward

Enchant permanent
Enchanted permanent has hexproof.
When enchanted permanent leaves the battlefield, if it was historic, draw two cards. (Artifacts, legendaries, and Sagas are historic.)

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.

Rishadan Footpad

When this creature enters, each opponent sacrifices a permanent of their choice unless they pay {2}.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. This land deals 1 damage to you.

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.)

Tranquil Cove

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {U}.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Spellseeker

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