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.)
Watcher for Tomorrow enters tapped.
When Watcher for Tomorrow leaves the battlefield, put the exiled card into its owner's hand.

Sea of Clouds

Sea of Clouds enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters, you may pay 2 life. If you don't, it enters tapped.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Momentary Blink

Exile target creature you control, then return it to the battlefield under its owner's control.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Touch the Spirit Realm

When Touch the Spirit Realm enters, exile up to one target artifact or creature until Touch the Spirit Realm leaves the battlefield.
Channel — {1}{W}, Discard Touch the Spirit Realm: Exile target artifact or creature. Return it to the battlefield under its owner's control at the beginning of the next end step.

Candlekeep Sage

Commander creatures you own have "When this creature enters or leaves the battlefield, draw a card."

Essence Flux

Exile target creature you control, then return that card to the battlefield under its owner's control. If it's a Spirit, put a +1/+1 counter on it.

Loran of the Third Path

Vigilance
When Loran of the Third Path enters, destroy up to one target artifact or enchantment.
{T}: You and target opponent each draw a card.

Journey to Nowhere

When Journey to Nowhere enters, exile target creature.
When Journey to Nowhere leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Plains

Teleportation Circle

At the beginning of your end step, exile up to one target artifact or creature you control, then return that card to the battlefield under its owner's control.

Venser, Shaper Savant

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

Rumor Gatherer

Alliance — Whenever another creature you control enters, scry 1. If this is the second time this ability has resolved this turn, draw a card instead.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Arcane Signet

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

Gold Pan

When Gold Pan enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: 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.)

Talisman of Progress

{T}: Add {C}.
{T}: Add {W} or {U}. Talisman of Progress deals 1 damage to you.

Reliquary Tower

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

Preston, the Vanisher

Whenever another nontoken creature you control enters, if it wasn't cast, create a token that's a copy of that creature, except it's a 0/1 white Illusion.
{1}{W}, Sacrifice five Illusions: Exile target nonland permanent.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Command Tower

Panharmonicon

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

Spirited Companion

When Spirited Companion enters, draw a card.

Fellwar Stone

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

Sun Titan

Vigilance
Whenever Sun Titan enters or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Teferi, Time Raveler

Each opponent can cast spells only any time they could cast a sorcery.
+1: Until your next turn, you may cast sorcery spells as though they had flash.
−3: Return up to one target artifact, creature, or enchantment to its owner's hand. Draw a card.

Glacial Fortress

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

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.

Far Traveler

Commander creatures you own have "At the beginning of your end step, exile up to one target tapped creature you control, then return it to the battlefield under its owner's control."

Planar Incision

Exile target artifact or creature, then return it to the battlefield under its owner's control with a +1/+1 counter on it.

Prairie Stream

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

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.

Flickerwisp

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

Lembas

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

Wall of Omens

Defender
When Wall of Omens enters, draw a card.

Circuit Mender

When Circuit Mender enters, you gain 2 life.
When Circuit Mender leaves the battlefield, draw a card.

Skycloud Expanse

Peregrine Drake

Flying
When Peregrine Drake enters, untap up to five lands.

Swan Song

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

Swords to Plowshares

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

Brago, King Eternal

Flying
Whenever Brago, King Eternal 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.

Blur

Exile target creature you control, then return that card to the battlefield under its owner's control.
Draw a card.

Dovin's Veto

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

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.

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.)

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 Reality Acid leaves the battlefield, enchanted permanent's controller sacrifices it.

Glorious Protector

Flash
Flying
When Glorious Protector enters, you may exile any number of non-Angel creatures you control until Glorious Protector leaves the battlefield.
Foretell {2}{W}

Skyclave Apparition

When Skyclave Apparition enters, exile up to one target nonland, nontoken permanent you don't control with mana value 4 or less.
When Skyclave Apparition 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.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Spellseeker

When Spellseeker 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.

Dawnbringer Cleric

When Dawnbringer Cleric enters, choose one —
• Cure Wounds — You gain 2 life.
• Dispel Magic — Destroy target enchantment.
• Gentle Repose — Exile target card from a graveyard.

Farewell

Choose one or more —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all graveyards.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Island

Charming Prince

When this creature enters, choose one —
• Scry 2.
• You gain 3 life.
• Exile another target creature you own. Return it to the battlefield under your control at the beginning of the next end step.

Soulherder

Whenever a creature is exiled from the battlefield, put a +1/+1 counter on Soulherder.
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.

Aether Channeler

When Aether Channeler enters, choose one —
• Create a 1/1 white Bird creature token with flying.
• Return another target nonland permanent to its owner's hand.
• Draw a card.

Azorius Signet

Kor Cartographer

When Kor Cartographer enters, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Oblivion Ring

When Oblivion Ring enters, exile another target nonland permanent.
When Oblivion Ring leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Cloud of Faeries

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

Thought Vessel

Sol Ring

Oji, the Exquisite Blade

When Oji, the Exquisite Blade enters, you gain 2 life and scry 2.
Whenever you cast your second spell each turn, exile up to one target creature you control, then return it to the battlefield under its owner's control.

Knight of the White Orchid

First strike
When Knight of the White Orchid enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

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.

Abdel Adrian, Gorion's Ward

When Abdel Adrian, Gorion's Ward enters, exile any number of other nonland permanents you control until Abdel Adrian leaves the battlefield. Create a 1/1 white Soldier creature token for each permanent exiled this way.
Choose a Background (You can have a Background as a second commander.)

Exotic Orchard

Restoration Angel

Flash
Flying
When Restoration Angel enters, you may exile target non-Angel creature you control, then return that card to the battlefield under your control.

Flicker of Fate

Exile target creature or enchantment, then return it to the battlefield under its owner's control.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

Felidar Guardian

When Felidar Guardian enters, you may exile another target permanent you control, then return that card to the battlefield under its owner's control.

Displacer Kitten

Avoidance — Whenever you cast a noncreature spell, exile up to one target nonland permanent you control, then return that card to the battlefield under its owner's control.

Fiend Hunter

When Fiend Hunter enters, you may exile another target creature.
When Fiend Hunter leaves the battlefield, return the exiled card to the battlefield under its owner's control.

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.

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.