Capture Sphere

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
When Capture Sphere enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Cloudkin Seer

Flying
When Cloudkin Seer enters the battlefield, draw a card.

Rite of Replication

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Aether Adept

When Aether Adept enters the battlefield, return target creature to its owner's hand.

Day of the Dragons

When Day of the Dragons enters the battlefield, exile all creatures you control. Then create that many 5/5 red Dragon creature tokens with flying.
When Day of the Dragons leaves the battlefield, sacrifice all Dragons you control. Then return the exiled cards to the battlefield under your control.

Guild Summit

When Guild Summit enters the battlefield, you may tap any number of untapped Gates you control. Draw a card for each Gate tapped this way.
Whenever a Gate enters the battlefield under your control, draw a card.

Cartouche of Knowledge

Enchant creature you control
When Cartouche of Knowledge enters the battlefield, draw a card.
Enchanted creature gets +1/+1 and has flying.

Sphinx of Uthuun

Flying
When Sphinx of Uthuun enters the battlefield, reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Spell Swindle

Counter target spell. Create X Treasure tokens, where X is that spell's mana value. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Arcane Adaptation

As Arcane Adaptation enters the battlefield, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Mysteries of the Deep

Draw two cards.
Landfall — If you had a land enter the battlefield under your control this turn, draw three cards instead.

False Demise

Enchant creature
When enchanted creature dies, return that card to the battlefield under your control.

Abduction

Enchant creature
When Abduction enters the battlefield, untap enchanted creature.
You control enchanted creature.
When enchanted creature dies, return that card to the battlefield under its owner's control.

Aspiring Aeronaut

Flying (This creature can't be blocked except by creatures with flying or reach.)
When Aspiring Aeronaut enters the battlefield, create a 1/1 colorless Thopter artifact creature token with flying.

Aquatic Incursion

When Aquatic Incursion enters the battlefield, create two 1/1 blue Merfolk creature tokens with hexproof. (They can't be the targets of spells or abilities your opponents control.)
{3}{U}: Target Merfolk can't be blocked this turn.

Breaching Leviathan

When Breaching Leviathan enters the battlefield, if you cast it from your hand, tap all nonblue creatures. Those creatures don't untap during their controllers' next untap steps.

Archaeomancer

When Archaeomancer enters the battlefield, return target instant or sorcery card from your graveyard to your hand.

Academy Journeymage

This spell costs {1} less to cast if you control a Wizard.
When Academy Journeymage enters the battlefield, return target creature an opponent controls to its owner's hand.

Naban, Dean of Iteration

If a Wizard entering the battlefield under your control causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Angler Drake

Flying
When Angler Drake enters the battlefield, you may return target creature to its owner's hand.

Renegade Doppelganger

Whenever another creature enters the battlefield under your control, you may have Renegade Doppelganger become a copy of that creature until end of turn. (If it does, it loses this ability for the rest of the turn.)

Stolen by the Fae

Return target creature with mana value X to its owner's hand. You create X 1/1 blue Faerie creature tokens with flying.

Masterful Replication

Choose one —
• Create two 3/3 colorless Golem artifact creature tokens.
• Choose target artifact you control. Each other artifact you control becomes a copy of that artifact until end of turn.

Kapsho Kitefins

Flying
Whenever Kapsho Kitefins or another creature enters the battlefield under your control, tap target creature an opponent controls.

Callous Oppressor

You may choose not to untap Callous Oppressor during your untap step.
As Callous Oppressor enters the battlefield, an opponent chooses a creature type.
{T}: Gain control of target creature that isn't of the chosen type for as long as Callous Oppressor remains tapped.

Fool's Demise

Enchant creature
When enchanted creature dies, return that card to the battlefield under your control.
When Fool's Demise is put into a graveyard from the battlefield, return Fool's Demise to its owner's hand.

Mirror Match

Cast this spell only during the declare blockers step.
For each creature attacking you or a planeswalker you control, create a token that's a copy of that creature and that's blocking that creature. Exile those tokens at end of combat.

Corridor Monitor

When Corridor Monitor enters the battlefield, untap target artifact or creature you control.

Chameleon Spirit

As Chameleon Spirit enters the battlefield, choose a color.
Chameleon Spirit's power and toughness are each equal to the number of permanents of the chosen color your opponents control.

Coral Barrier

Defender (This creature can't attack.)
When Coral Barrier enters the battlefield, create a 1/1 blue Squid creature token with islandwalk. (It can't be blocked as long as defending player controls an Island.)

Aquamorph Entity

As Aquamorph Entity enters the battlefield or is turned face up, it becomes your choice of 5/1 or 1/5.
Morph {2}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Charmed Sleep

Enchant creature
When Charmed Sleep enters the battlefield, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Aven Fogbringer

Flying
When Aven Fogbringer enters the battlefield, return target land to its owner's hand.

Prosperous Pirates

When Prosperous Pirates enters the battlefield, create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Alirios, Enraptured

Alirios, Enraptured enters the battlefield tapped.
Alirios doesn't untap during your untap step if you control a Reflection.
When Alirios enters the battlefield, create a 3/2 blue Reflection creature token.

Academy Elite

Academy Elite enters the battlefield with X +1/+1 counters on it, where X is the number of instant and sorcery cards in all graveyards.
{2}{U}, Remove a +1/+1 counter from Academy Elite: Draw a card, then discard a card.

Thought Reflection

If you would draw a card, draw two cards instead.

Bazaar of Wonders

When Bazaar of Wonders enters the battlefield, exile all graveyards.
Whenever a player casts a spell, counter it if a card with the same name is in a graveyard or a nontoken permanent with the same name is on the battlefield.

Experimental Aviator

Flying
When Experimental Aviator enters the battlefield, create two 1/1 colorless Thopter artifact creature tokens with flying.

Retreat to Coralhelm

Landfall — Whenever a land enters the battlefield under your control, choose one —
• You may tap or untap target creature.
• Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Guardian of Tazeem

Flying
Landfall — Whenever a land enters the battlefield under your control, tap target creature an opponent controls. If that land is an Island, that creature doesn't untap during its controller's next untap step.

Armored Skaab

When Armored Skaab enters the battlefield, mill four cards.

Mirrodin Besieged

As Mirrodin Besieged enters the battlefield, choose Mirran or Phyrexian.
• Mirran — Whenever you cast an artifact spell, create a 1/1 colorless Myr artifact creature token.
• Phyrexian — At the beginning of your end step, draw a card, then discard a card. Then if there are fifteen or more artifact cards in your graveyard, target opponent loses the game.

Breaching Hippocamp

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

Chancellor of the Spires

You may reveal this card from your opening hand. If you do, at the beginning of the first upkeep, each opponent mills seven cards.
Flying
When Chancellor of the Spires enters the battlefield, you may cast target instant or sorcery card from an opponent's graveyard without paying its mana cost.

Aethersnipe

When Aethersnipe enters the battlefield, return target nonland permanent to its owner's hand.
Evoke {1}{U}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters the battlefield.)

Agent of Treachery

When Agent of Treachery enters the battlefield, 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.

Aviation Pioneer

When Aviation Pioneer enters the battlefield, create a 1/1 colorless Thopter artifact creature token with flying.

Captain of the Mists

Whenever another Human enters the battlefield under your control, untap Captain of the Mists.
{1}{U}, {T}: You may tap or untap target permanent.

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.