Ripples of Potential

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

Stall for Time

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Tap up to two target creatures. If this spell was kicked, put a stun counter on each of those creatures. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Draw a card.

Referee Squad

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Vigilance
When this creature enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Amazing Acrobatics

Choose one or both —
• Counter target spell.
• Tap one or two target creatures.

Stall Out

Tap target creature or Vehicle, then put three stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Cycling {2} ({2}, Discard this card: Draw a card.)

Succumb to the Cold

Tap one or two target creatures an opponent controls. Put a stun counter on each of them. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Aerith Rescue Mission

Choose one —
• Take the Elevator — Create three 1/1 colorless Hero creature tokens.
• Take 59 Flights of Stairs — Tap up to three target creatures. Put a stun counter on one of them. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Assassin Gauntlet

When this Equipment enters, attach it to up to one target creature you control. Tap all creatures target opponent controls.
Equipped creature gets +1/+1 and has "Whenever this creature deals combat damage to a player, draw a card, then discard a card."
Equip {2}

Wicked Slumber

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Tap up to two target creatures. Put a stun counter on either of them. Then put a stun counter on either of them. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Web-Shooters

Equipped creature gets +1/+1 and has reach and "Whenever this creature attacks, tap target creature an opponent controls."
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Plains

Trap the Trespassers

Secret council — Each player secretly votes for a creature you don't control, then those votes are revealed. For each creature with one or more votes, put that many stun counters on it, then tap it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Sanctuary Wall

Defender
{2}{W}, {T}: Tap target creature. You may put a stun counter on it. If you do, put a stun counter on this creature. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Kitnap

Gift a card (You may promise an opponent a gift as you cast this spell. If you do, when it enters, they draw a card.)
Enchant creature
When this Aura enters, tap enchanted creature. If the gift wasn't promised, put three stun counters on it.
You control enchanted creature.

Arid Archway

This land enters tapped.
When this land enters, return a land you control to its owner's hand. If another Desert was returned this way, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
{T}: Add {C}{C}.

Summon: Shiva

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Heavenly Strike — Tap target creature an opponent controls. Put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
III — Diamond Dust — Draw a card for each tapped creature your opponents control.

Thassa's Oracle

When this creature enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Freeze in Place

Tap target creature an opponent controls and put three stun counters on it. Scry 2. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Command Tower

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

Metastatic Evangel

Whenever another nontoken creature you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Daily Bugle Building

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
Smear Campaign — {1}, {T}: Target legendary creature gains menace until end of turn. Activate only as a sorcery.

Sway of the Stars

Each player shuffles their hand, graveyard, and all permanents they own into their library, then draws seven cards. Each player's life total becomes 7.

Island

Out Cold

This spell can't be countered. (This includes by the ward ability.)
Tap up to two target creatures and put a stun counter on each of them. Investigate. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Sudden Strike

Destroy target attacking or blocking creature.

Lyla, Holographic Assistant

Whenever you draw a card, put a +1/+1 counter on target creature.

Mjölnir, Storm Hammer

When Mjölnir enters, attach it to target legendary creature you control.
Whenever equipped creature attacks, tap target creature defending player controls and put a stun counter on it. Then Mjölnir deals damage to each opponent equal to the number of tapped creatures that opponent controls.
Equip {4}

Shackle Slinger

Whenever you cast your second spell each turn, choose target creature an opponent controls. If it's tapped, put a stun counter on it. Otherwise, tap it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Caduceus, Staff of Hermes

Equipped creature has lifelink.
As long as you have 30 or more life, equipped creature gets +5/+5 and has indestructible and "Prevent all damage that would be dealt to this creature."
Equip {W}{W}

Deserted Beach

This land enters tapped unless you control two or more other lands.
{T}: Add {W} or {U}.

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.

Anchor to Reality

As an additional cost to cast this spell, sacrifice an artifact or creature.
Search your library for an Equipment or Vehicle card, put that card onto the battlefield, then shuffle. If it has mana value less than the sacrificed permanent's mana value, scry 2.

Timin, Youthful Geist

Partner with Rhoda, Geist Avenger (When this creature enters, target player may put Rhoda into their hand from their library, then shuffle.)
Flying
At the beginning of each combat, tap up to one target creature.

Archway of Innovation

This land enters tapped unless you control an Island.
{T}: Add {U}.
{U}, {T}: The next spell you cast this turn has improvise. (Your artifacts can help cast that spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Floodpits Drowner

Flash
Vigilance
When this creature enters, tap target creature an opponent controls and put a stun counter on it.
{1}{U}, {T}: Shuffle this creature and target creature with a stun counter on it into their owners' libraries.

Rhoda, Geist Avenger

Partner with Timin, Youthful Geist (When this creature enters, target player may put Timin into their hand from their library, then shuffle.)
Vigilance
Whenever a creature an opponent controls becomes tapped, if it isn't being declared as an attacker, put a +1/+1 counter on Rhoda.

Sun-Spider, Nimble Webber

During your turn, Sun-Spider has flying.
When Sun-Spider enters, search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Hylda of the Icy Crown

Whenever you tap an untapped creature an opponent controls, you may pay {1}. When you do, choose one —
• Create a 4/4 white and blue Elemental creature token.
• Put a +1/+1 counter on each creature you control.
• Scry 2, then draw a card.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Brotherhood Regalia

Equipped creature has ward {2}, is an Assassin in addition to its other types, and can't be blocked.
Equip legendary creature {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Eon Frolicker

Flying
When this creature enters, if you cast it, target opponent takes an extra turn after this one. Until your next turn, you and planeswalkers you control gain protection from that player. (You and planeswalkers you control can't be targeted, dealt damage, or enchanted by anything controlled by that player.)

Grappling Kraken

Landfall — Whenever a land you control enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Wraith, Vicious Vigilante

Double strike
Fear Gas — Wraith can't be blocked.

Fear of Sleep Paralysis

Flying
Eerie — Whenever this creature or another enchantment you control enters and whenever you fully unlock a Room, tap up to one target creature and put a stun counter on it.
Stun counters can't be removed from permanents your opponents control. (They won't untap if they have stun counters.)

Coastal Tower

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

Impede Momentum

Tap target creature and put three stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Ultros, Obnoxious Octopus

Whenever you cast a noncreature spell, if at least four mana was spent to cast it, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you cast a noncreature spell, if at least eight mana was spent to cast it, put eight +1/+1 counters on Ultros.

Norn's Choirmaster

Flying, first strike
Whenever a commander you control enters or attacks, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Teferi, Master of Time

You may activate loyalty abilities of Teferi on any player's turn any time you could cast an instant.
+1: Draw a card, then discard a card.
−3: Target creature you don't control phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)
−10: Take two extra turns after this one.

Ancient Den

Alchemax Slayer-Bots

When this creature enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Apple of Eden, Isu Relic

{T}, Pay 4 life, Sacrifice Apple of Eden: Look at target opponent's hand and exile those cards face down. You may play those cards this turn, and mana of any type can be spent to cast them. Until end of turn, whenever you play a land or cast a spell this way, its owner draws a card. At the beginning of the next end step, return the exiled cards to their owner's hand. Activate only as a sorcery.

Arachne, Psionic Weaver

Web-slinging {W} (You may cast this spell for {W} if you also return a tapped creature you control to its owner's hand.)
As Arachne enters, look at an opponent's hand, then choose a card type other than creature.
Spells of the chosen type cost {1} more to cast.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Sensational Spider-Man

Whenever Sensational Spider-Man attacks, tap target creature defending player controls and put a stun counter on it. Then you may remove up to three stun counters from among all permanents. Draw cards equal to the number of stun counters removed this way.

Deadeye Quartermaster

When this creature enters, you may search your library for an Equipment or Vehicle card, reveal it, put it into your hand, then shuffle.

Eden, Seat of the Sanctum

{T}: Add {C}.
{5}, {T}: Mill two cards. Then you may sacrifice this land. When you do, return another target permanent card from your graveyard to your hand.

Spider-Woman, Stunning Savior

Flying
Venom Blast — Artifacts and creatures your opponents control enter tapped.

Thought Vessel

Spider-Sense

Web-slinging {U} (You may cast this spell for {U} if you also return a tapped creature you control to its owner's hand.)
Counter target instant spell, sorcery spell, or triggered ability.

Crystal Skull, Isu Spyglass

You may look at the top card of your library any time.
You may play historic lands and cast historic spells from the top of your library. (Artifacts, legendaries, and Sagas are historic.)
{T}: Add {U}.

Kindred Discovery

As this enchantment enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Sleep-Cursed Faerie

Flying, ward {2}
This creature enters tapped with three stun counters on it. (If it would become untapped, remove a stun counter from it instead.)
{1}{U}: Untap this creature.

The Watcher in the Water

The Watcher in the Water enters tapped with nine stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you draw a card during an opponent's turn, create a 1/1 blue Tentacle creature token.
Whenever a Tentacle you control dies, untap up to one target Kraken and put a stun counter on up to one target nonland permanent.

SP//dr, Piloted by Peni

Vigilance
When SP//dr enters, put a +1/+1 counter on target creature.
Whenever a modified creature you control deals combat damage to a player, draw a card. (Equipment, Auras you control, and counters are modifications.)

Clive's Hideaway

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
{T}: Add {C}.
{2}, {T}: You may play the exiled card without paying its mana cost if you control four or more legendary creatures.

Azorius Chancery

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

Sage of the Falls

Whenever this creature or another non-Human creature you control enters, you may draw a card. If you do, discard a card.

Sharae of Numbing Depths

When Sharae enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you tap one or more untapped creatures your opponents control, draw a card. This ability triggers only once each turn.

Moon-Blessed Cleric

Divine Intervention — When this creature enters, you may search your library for an enchantment card, reveal it, then shuffle and put that card on top.

Coastal Piracy

Whenever a creature you control deals combat damage to an opponent, you may draw a card.

Lost in the Maze

Flash
When this enchantment enters, tap X target creatures. Put a stun counter on each of those creatures you don't control. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Tapped creatures you control have hexproof.

Cloud's Limit Break

Tiered (Choose one additional cost.)
• Cross-Slash — {0} — Destroy target tapped creature.
• Blade Beam — {1} — Destroy any number of target tapped creatures with different controllers.
• Omnislash — {3}{W} — Destroy all tapped creatures.

Tranquilize

Tap target creature an opponent controls and put three stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Loyal Inventor

Vigilance
When this creature enters, you may search your library for an artifact card, reveal it, then shuffle. Put that card into your hand if you control an Assassin. Otherwise, put that card on top of your library.

Thwip!

Target creature gets +2/+2 and gains flying until end of turn. If it's a Spider, you gain 2 life.

Splash Lasher

Offspring {1}{U} (You may pay an additional {1}{U} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
When this creature enters, tap up to one target creature and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Drift of Phantasms

Defender (This creature can't attack.)
Flying
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Diamond City

This land enters with a shield counter on it. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
{T}: Add {C}.
{T}: Move a shield counter from this land onto target creature. Activate only if two or more creatures entered the battlefield under your control this turn.

Lulu, Stern Guardian

Whenever an opponent attacks you, choose target creature attacking you. Put a stun counter on that creature.
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Solitary Sanctuary

When this enchantment enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you tap an untapped creature an opponent controls, put a +1/+1 counter on target creature you control.