Space Marine Scout

First strike, vigilance
Concealed Position — When Space Marine Scout enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Harbinger of the Tides

You may cast this card as though it had flash if you pay {2} more to cast it. (You may cast it any time you could cast an instant.)
When this creature enters, you may return target tapped creature an opponent controls to its owner's hand.

Meteor Golem

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

Detention Sphere

When Detention Sphere enters, you may exile target nonland permanent not named Detention Sphere and all other permanents with the same name as that permanent.
When Detention Sphere leaves the battlefield, return the exiled cards to the battlefield under their owner's control.

Faith's Fetters

Enchant permanent
When Faith's Fetters 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.

Ajani's Chosen

Whenever an enchantment you control enters, create a 2/2 white Cat creature token. If that enchantment is an Aura, you may attach it to the token.

Court Street Denizen

Whenever another white creature you control enters, tap target creature an opponent controls.

Mentor of the Meek

Whenever another creature you control with power 2 or less enters, you may pay {1}. If you do, draw a card.

Heliod's Pilgrim

When Heliod's Pilgrim enters, you may search your library for an Aura card, reveal it, put it into your hand, then shuffle.

Omenspeaker

When Omenspeaker enters, 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.)

Gallant Cavalry

Vigilance (Attacking doesn't cause this creature to tap.)
When Gallant Cavalry enters, create a 2/2 white Knight creature token with vigilance.

Mace of the Valiant

Equipped creature gets +1/+1 for each charge counter on Mace of the Valiant and has vigilance. (Attacking doesn't cause it to tap.)
Whenever a creature you control enters, put a charge counter on Mace of the Valiant.
Equip {3}

Tome Raider

Flying
When Tome Raider enters, draw a card.

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.

Sunblast Angel

Flying
When Sunblast Angel enters, destroy all tapped creatures.

Scrollshift

Exile up to one target artifact, creature, or enchantment you control, then return it to the battlefield under its owner's control.
Draw a card.

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.

Sailor of Means

When Sailor of Means enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Evangel of Heliod

When Evangel of Heliod 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.)

Meandering River

Meandering River enters tapped.
{T}: Add {W} or {U}.

Sage's Reverie

Enchant creature
When Sage's Reverie enters, draw a card for each Aura you control that's attached to a creature.
Enchanted creature gets +1/+1 for each Aura you control that's attached to a creature.

Plains

Sphinx of Enlightenment

Flying
When Sphinx of Enlightenment enters, target opponent draws a card and you draw three cards.

Hallowed Fountain

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

Impassioned Orator

Whenever another creature you control enters, you gain 1 life.

Island

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.

Ninth Bridge Patrol

Whenever another creature you control leaves the battlefield, put a +1/+1 counter on Ninth Bridge Patrol.

Knightly Valor

Enchant creature
When Knightly Valor enters, create a 2/2 white Knight creature token with vigilance. (Attacking doesn't cause it to tap.)
Enchanted creature gets +2/+2 and has vigilance.

Flicker of Fate

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

Arcane Signet

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

Sage's Row Denizen

Whenever another blue creature you control enters, target player mills two cards.

Mage's Attendant

When Mage's Attendant enters, create a 1/1 blue Wizard creature token with "{1}, Sacrifice this creature: Counter target noncreature spell unless its controller pays {1}."

Siren Lookout

Flying
When Siren Lookout enters, it explores. (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 this creature, then put the card back or put it into your graveyard.)

Kor Cartographer

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

Highcliff Felidar

Vigilance
When Highcliff Felidar enters, for each opponent, choose a creature with the greatest power among creatures that player controls. Destroy those creatures.

Azure Fleet Admiral

When Azure Fleet Admiral enters, you become the monarch.
Azure Fleet Admiral can't be blocked by creatures the monarch controls.

Azorius Chancery

Azorius Chancery enters tapped.
When Azorius Chancery enters, return a land you control to its owner's hand.
{T}: Add {W}{U}.

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.

Cataclysmic Gearhulk

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

Benevolent Blessing

Flash
Enchant creature
As Benevolent Blessing enters, choose a color.
Enchanted creature has protection from the chosen color. This effect doesn't remove Auras and Equipment you control that are already attached to it.

Dungeon Geists

Flying
When Dungeon Geists enters, tap target creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Dungeon Geists.

Clarion Cathars

When Clarion Cathars enters, create a 1/1 white Human creature token.

Court Hussar

Vigilance
When Court Hussar enters, look at the top three cards of your library, then put one of them into your hand and the rest on the bottom of your library in any order.
When Court Hussar enters, sacrifice it unless {W} was spent to cast it.

Deputy of Acquittals

Flash (You may cast this spell any time you could cast an instant.)
When Deputy of Acquittals enters, you may return another target creature you control to its owner's hand.

Disdainful Stroke

Counter target spell with mana value 4 or greater.

Space Marine Devastator

Squad {2} (As an additional cost to cast this spell, you may pay {2} any number of times. When this creature enters, create that many tokens that are copies of it.)
Grav-cannon — When Space Marine Devastator enters, destroy up to one target artifact or enchantment.

Whitewater Naiads

Constellation — Whenever Whitewater Naiads or another enchantment you control enters, target creature can't be blocked this turn.

Supreme Will

Choose one —
• Counter target spell unless its controller pays {3}.
• Look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Keymaster Rogue

Keymaster Rogue can't be blocked.
When Keymaster Rogue enters, return a creature you control to its owner's hand.

Irrigated Farmland

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

Daxos, Blessed by the Sun

Daxos's toughness is equal to your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)
Whenever another creature you control enters or dies, you gain 1 life.

Sea Gate Oracle

When Sea Gate Oracle 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.

Amphin Mutineer

When Amphin Mutineer enters, exile up to one target non-Salamander creature. That creature's controller creates a 4/3 blue Salamander Warrior creature token.
Encore {4}{U}{U} ({4}{U}{U}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Lavinia of the Tenth

Protection from red
When Lavinia of the Tenth 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.)

Pilgrim's Eye

Flying
When Pilgrim's Eye enters, you may search your library for a basic land card, reveal it, put it into your hand, then shuffle.

Tempest Caller

When Tempest Caller enters, tap all creatures target opponent controls.

Metamorphic Alteration

Enchant creature
As Metamorphic Alteration enters, choose a creature.
Enchanted creature is a copy of the chosen creature.

Unquestioned Authority

Enchant creature
When Unquestioned Authority enters, draw a card.
Enchanted creature has protection from creatures.

Icefall Regent

Flying
When Icefall Regent enters, tap target creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control Icefall Regent.
Spells your opponents cast that target Icefall Regent cost {2} more to cast.

Celebrity Fencer

Alliance — Whenever another creature you control enters, put a +1/+1 counter on Celebrity Fencer.

Sol Ring

Fall from Favor

Enchant creature
When Fall from Favor enters, tap enchanted creature and you become the monarch.
Enchanted creature doesn't untap during its controller's untap step unless that player is the monarch.

Agent of Treachery

When Agent of Treachery 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.

Lord of Change

Flying, ward {3}
Architect of Deception — When Lord of Change enters, draw three cards.

Scourge of Fleets

When Scourge of Fleets enters, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

Inspired Sphinx

Flying
When Inspired Sphinx enters, draw cards equal to the number of opponents you have.
{3}{U}: Create a 1/1 colorless Thopter artifact creature token with flying.

Mesmerizing Benthid

When Mesmerizing Benthid enters, create two 0/2 blue Illusion creature tokens with "Whenever this creature blocks a creature, that creature doesn't untap during its controller's next untap step."
Mesmerizing Benthid has hexproof as long as you control an Illusion.

Repulse

Return target creature to its owner's hand.
Draw a card.

Azorius Guildgate

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

Salvager of Secrets

When Salvager of Secrets enters, return target instant or sorcery card from your graveyard to your hand.

Estrid's Invocation

You may have Estrid's Invocation enter as a copy of an enchantment you control, except it has "At the beginning of your upkeep, you may exile this enchantment. If you do, return it to the battlefield under its owner's control."