Ring of Three Wishes

Ring of Three Wishes enters with three wish counters on it.
{5}, {T}, Remove a wish counter from Ring of Three Wishes: Search your library for a card, put that card into your hand, then shuffle.

Emeria Shepherd

Flying
Landfall — Whenever a land you control enters, you may return target nonland permanent card from your graveyard to your hand. If that land is a Plains, you may return that nonland permanent card to the battlefield instead.

Disenchant

Cavalier of Dawn

Vigilance
When Cavalier of Dawn enters, destroy up to one target nonland permanent. Its controller creates a 3/3 colorless Golem artifact creature token.
When Cavalier of Dawn dies, return target artifact or enchantment card from your graveyard to your hand.

Archivist of Oghma

Flash
Whenever an opponent searches their library, you gain 1 life and draw a card.

Altar of the Brood

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

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.

Distinguished Conjurer

Whenever another creature you control enters, you gain 1 life.
{4}{W}, {T}: Exile another target creature you control, then return it to the battlefield under its owner's control.

Tocasia's Welcome

Whenever one or more creatures you control with mana value 3 or less enter, draw a card. This ability triggers only once each turn.

Forbidding Spirit

When Forbidding Spirit enters, until your next turn, creatures can't attack you or planeswalkers you control unless their controller pays {2} for each of those creatures.

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Rest in Peace

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

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.

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.

Darksteel Mutation

Enchant creature
Enchanted creature is an Insect artifact creature with base power and toughness 0/1 and has indestructible, and it loses all other abilities, card types, and creature types.

Thalia, Heretic Cathar

First strike
Creatures and nonbasic lands your opponents control enter tapped.

Suture Priest

Whenever another creature you control enters, you may gain 1 life.
Whenever a creature an opponent controls enters, you may have that player lose 1 life.

Lightning Greaves

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

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.")

Grand Abolisher

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.

Regal Caracal

Other Cats you control get +1/+1 and have lifelink.
When Regal Caracal enters, create two 1/1 white Cat creature tokens with lifelink.

Panharmonicon

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

Soul Warden

Whenever another creature enters, you gain 1 life.

Aerial Extortionist

Flying
Whenever Aerial Extortionist enters or deals combat damage to a player, exile up to one target nonland permanent. For as long as that card remains exiled, its owner may cast it.
Whenever another player casts a spell from anywhere other than their hand, draw a card.

Leonin Relic-Warder

When Leonin Relic-Warder enters, you may exile target artifact or enchantment.
When Leonin Relic-Warder leaves the battlefield, return the exiled card to the battlefield under its owner's control.

Master Splicer

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

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.

Aetherflux Reservoir

Whenever you cast a spell, you gain 1 life for each spell you've cast this turn.
Pay 50 life: Aetherflux Reservoir deals 50 damage to any target.

Cast Out

Flash
When Cast Out enters, exile target nonland permanent an opponent controls until Cast Out leaves the battlefield.
Cycling {W} ({W}, Discard this card: Draw a card.)