Sol Ring

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.

Bigfin Bouncer

When this creature enters, return target creature an opponent controls to its owner's hand.

Neoform

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a creature card with mana value equal to 1 plus the sacrificed creature's mana value, put that card onto the battlefield with an additional +1/+1 counter on it, then shuffle.

Great Oak Guardian

Flash (You may cast this spell any time you could cast an instant.)
Reach
When this creature enters, creatures target player controls get +2/+2 until end of turn. Untap them.

Riftwing Cloudskate

Flying
When this creature enters, return target permanent to its owner's hand.
Suspend 3—{1}{U} (Rather than cast this card from your hand, you may pay {1}{U} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)

Progenitor Mimic

You may have this creature enter as a copy of any creature on the battlefield, except it has "At the beginning of your upkeep, if this creature isn't a token, create a token that's a copy of this creature."

Tidal Force

At the beginning of each upkeep, you may tap or untap target permanent.

Aggressive Biomancy

Create X tokens that are copies of target creature you control, except they have "When this token enters, it fights up to one target creature you don't control."

Wood Elves

When this creature enters, search your library for a Forest card, put that card onto the battlefield, then shuffle.

Island

Reclamation Sage

When this creature enters, you may destroy target artifact or enchantment.

Elvish Mystic

Gilded Goose

Flying
When this creature enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
{1}{G}, {T}: Create a Food token.
{T}, Sacrifice a Food: Add one mana of any color.

Armored Scrapgorger

This creature gets +3/+0 as long as it has three or more oil counters on it.
{T}: Add one mana of any color.
Whenever this creature becomes tapped, exile target card from a graveyard and put an oil counter on this creature.

Kiora's Follower

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Aboleth Spawn

Flash
Ward {2}
Probing Telepathy — Whenever a creature entering under an opponent's control causes a triggered ability of that creature to trigger, you may copy that ability. You may choose new targets for the copy.

Druid of Purification

When this creature enters, starting with you, each player may choose an artifact or enchantment you don't control. Destroy each permanent chosen this way.

Eldritch Evolution

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a creature card with mana value X or less, where X is 2 plus the sacrificed creature's mana value. Put that card onto the battlefield, then shuffle. Exile Eldritch Evolution.

Tidespout Tyrant

Flying
Whenever you cast a spell, return target permanent to its owner's hand.

Mind Flayer

Dominate Monster — When this creature enters, gain control of target creature for as long as you control this creature.

Arbor Elf

Verdant Sun's Avatar

Whenever this creature or another creature you control enters, you gain life equal to that creature's toughness.

Tale's End

Counter target activated ability, triggered ability, or legendary spell.

Fyndhorn Elves

Loaming Shaman

When this creature enters, target player shuffles any number of target cards from their graveyard into their library.

Scurry Oak

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on this creature, you may create a 1/1 green Squirrel creature token.

Gruff Triplets

Trample
When this creature enters, if it isn't a token, create two tokens that are copies of it.
When this creature dies, put a number of +1/+1 counters equal to its power on each creature you control named Gruff Triplets.

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.")

Bramble Sovereign

Whenever another nontoken creature enters, you may pay {1}{G}. If you do, that creature's controller creates a token that's a copy of that creature.

Frilled Mystic

Flash
When this creature enters, you may counter target spell.

Altered Ego

This spell can't be countered.
You may have this creature enter as a copy of any creature on the battlefield, except it enters with X additional +1/+1 counters on it.

Farhaven Elf

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

Eternal Witness

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

Rooting Kavu

When this creature dies, you may exile it. If you do, shuffle all creature cards from your graveyard into your library.

Fear of Impostors

Flash
When this creature enters, counter target spell. 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.)

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Prime Speaker Vannifar

{T}, Sacrifice another creature: Search your library for a creature card with mana value equal to 1 plus the sacrificed creature's mana value, put that card onto the battlefield, then shuffle. Activate only as a sorcery.

Deadly Recluse

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Body Double

You may have this creature enter as a copy of any creature card in a graveyard.

Thornweald Archer

Corridor Monitor

When this creature enters, untap target artifact or creature you control.

Forest

Peregrine Drake

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

Coiling Oracle

When this creature enters, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put that card into your hand.

Mystic Snake

Flash
When this creature enters, counter target spell.

Lilysplash Mentor

Reach
{1}{G}{U}: Exile another target creature you control, then return it to the battlefield under its owner's control with a +1/+1 counter on it. Activate only as a sorcery.

Starfield Vocalist

If a permanent entering the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Warp {1}{U} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Bane of Progress

When this creature enters, destroy all artifacts and enchantments. Put a +1/+1 counter on this creature for each permanent destroyed this way.

Quirion Ranger

Return a Forest you control to its owner's hand: Untap target creature. Activate only once each turn.

Augury Owl

Flying
When this creature enters, scry 3. (Look at the top three cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Llanowar Elves

Boreal Druid

Mana Leak

Counter target spell unless its controller pays {3}.

Vantress Visions

Copy target activated or triggered ability you control. You may choose new targets for the copy.

Virtue of Knowledge

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

Virtue of Knowledge // Vantress Visions

Dryad Arbor

(This land isn't a spell, it's affected by summoning sickness, and it has "{T}: Add {G}.")

Man-o'-War

When this creature enters, return target creature to its owner's hand.

Seedborn Muse

Untap all permanents you control during each other player's untap step.

Collector Ouphe

Activated abilities of artifacts can't be activated.

Ioreth of the Healing House

{T}: Untap another target permanent.
{T}: Untap two other target legendary creatures.

Murkfiend Liege

Other green creatures you control get +1/+1.
Other blue creatures you control get +1/+1.
Untap all green and/or blue creatures you control during each other player's untap step.

Dragon Sniper

Breaching Hippocamp

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

Endurance

Flash
Reach
When this creature enters, up to one target player puts all the cards from their graveyard on the bottom of their library in a random order.
Evoke—Exile a green card from your hand.

Protean Hulk

When this creature dies, search your library for any number of creature cards with total mana value 6 or less, put them onto the battlefield, then shuffle.

Birds of Paradise

Springbloom Druid

When this creature enters, you may sacrifice a land. If you do, search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Hyrax Tower Scout

When this creature enters, untap target creature.

Ivy Lane Denizen

Whenever another green creature you control enters, put a +1/+1 counter on target creature.