Felidar Guardian

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

Ertha Jo, Frontier Mentor

When Ertha Jo enters, create a 1/1 red Mercenary creature token with "{T}: Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery."
Whenever you activate an ability that targets a creature or player, copy that ability. You may choose new targets for the copy.

Gold Myr

Command Tower

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

Mage's Attendant

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

Mountain

Goblin Bombardment

Sacrifice a creature: This enchantment deals 1 damage to any target.

Exotic Orchard

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

The Jolly Balloon Man

Haste
{1}, {T}: Create a token that's a copy of another target creature you control, except it's a 1/1 red Balloon creature in addition to its other colors and types and it has flying and haste. Sacrifice it at the beginning of the next end step. Activate only as a sorcery.

Plains

Arcane Signet

Village Bell-Ringer

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, untap all creatures you control.

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.

Spirited Companion

Zealous Conscripts

Haste
When this creature enters, gain control of target permanent until end of turn. Untap that permanent. It gains haste until end of turn.

Swords to Plowshares

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

Professional Face-Breaker

Menace
Whenever one or more creatures you control deal combat damage to a player, create a Treasure token.
Sacrifice a Treasure: Exile the top card of your library. You may play that card this turn.

Patron of the Arts

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

Cursed Mirror

{T}: Add {R}.
As this artifact enters, you may have it become a copy of any creature on the battlefield until end of turn, except it has haste.

Patriar's Seal

{T}: Add one mana of any color.
{1}, {T}: Untap target legendary creature you 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.

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.

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.

Clifftop Retreat

This land enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Anointed Procession

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Karmic Guide

Flying, protection from black
Echo {3}{W}{W} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters, return target creature card from your graveyard to the battlefield.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Sol Ring

Battlefield Forge

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

Circuit Mender

When this creature enters, you gain 2 life.
When this creature leaves the battlefield, draw a card.

Sun Titan

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

Bovine Intervention

Destroy target artifact or creature. Its controller creates a 2/2 white Ox creature token.

Iron Myr

Coercive Recruiter

Whenever this creature or another Pirate you control enters, gain control of target creature until end of turn. Untap that creature. Until end of turn, it gains haste and becomes a Pirate in addition to its other types.

Recruiter of the Guard

When this creature enters, you may search your library for a creature card with toughness 2 or less, reveal it, put it into your hand, then shuffle.

Boros Signet

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.)

Enduring Innocence

Lifelink
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.
When Enduring Innocence dies, if it was a creature, return it to the battlefield under its owner's control. It's an enchantment. (It's not a creature.)

Panharmonicon

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

Life of the Party

First strike, trample, haste
Whenever this creature attacks, it gets +X/+0 until end of turn, where X is the number of creatures you control.
When this creature enters, if it's not a token, each opponent creates a token that's a copy of it. The tokens are goaded for the rest of the game. (They attack each combat if able and attack a player other than you if able.)

Rugged Prairie

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

Determined Iteration

At the beginning of combat on your turn, populate. The token created this way gains haste. Sacrifice it at the beginning of the next end step. (To populate, create a token that's a copy of a creature token you control.)

Austere Command

Choose two —
• Destroy all artifacts.
• Destroy all enchantments.
• Destroy all creatures with mana value 3 or less.
• Destroy all creatures with mana value 4 or greater.

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. This artifact deals 1 damage to you.

Magewright's Stone

{1}, {T}: Untap target creature that has an activated ability with {T} in its cost.

Restoration Angel

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

Inspiring Overseer

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

Blade Splicer

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

Palladium Myr

Impact Tremors

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

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Lightning Greaves

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

Skullclamp

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

Ornithopter of Paradise

Unwanted Remake

Destroy target creature. Its controller manifests dread. (That player looks at the top two cards of their library, then puts one onto the battlefield face down as a 2/2 creature and the other into their graveyard. If it's a creature card, it can be turned face up any time for its mana cost.)

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice this artifact: Create a 10/10 colorless Eldrazi creature token.