Cowed by Wisdom

Enchant creature
Enchanted creature can't attack or block unless its controller pays {1} for each card in your hand.

Semblance Anvil

Imprint — When Semblance Anvil enters, you may exile a nonland card from your hand.
Spells you cast that share a card type with the exiled card cost {2} less to cast.

Damping Sphere

If a land is tapped for two or more mana, it produces {C} instead of any other type and amount.
Each spell a player casts costs {1} more to cast for each other spell that player has cast this turn.

Ith, High Arcanist

Vigilance
{T}: Untap target attacking creature. Prevent all combat damage that would be dealt to and dealt by that creature this turn.
Suspend 4—{W}{U}

Well of Lost Dreams

Whenever you gain life, you may pay {X}, where X is less than or equal to the amount of life you gained. If you do, draw X cards.

Glowrider

Noncreature spells cost {1} more to cast.

Ghost-Lit Warder

{3}{U}, {T}: Counter target spell unless its controller pays {2}.
Channel — {3}{U}, Discard Ghost-Lit Warder: Counter target spell unless its controller pays {4}.

Exiled Doomsayer

All morph costs cost {2} more. (This doesn't affect the cost to cast creature spells face down.)

Stormscape Familiar

Flying
White spells and black spells you cast cost {1} less to cast.

Azorius Chancery

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

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}.

Soul Barrier

Whenever an opponent casts a creature spell, Soul Barrier deals 2 damage to that player unless they pay {2}.

Thalia, Guardian of Thraben

First strike
Noncreature spells cost {1} more to cast.

Overrule

Counter target spell unless its controller pays {X}. You gain X life.

Mana Chains

Enchant creature
Enchanted creature has "Cumulative upkeep {1}." (At the beginning of its controller's upkeep, that player puts an age counter on it, then sacrifices it unless they pay its upkeep cost for each age counter on it.)

Leonin Arbiter

Players can't search libraries. Any player may pay {2} for that player to ignore this effect until end of turn.

Nils, Discipline Enforcer

At the beginning of your end step, for each player, put a +1/+1 counter on up to one target creature that player controls.
Each creature with one or more counters on it can't attack you or planeswalkers you control unless its controller pays {X}, where X is the number of counters on that creature.

Sphere of Resistance

Fade Away

For each creature, its controller sacrifices a permanent of their choice unless they pay {1}.

Sun Droplet

Whenever you're dealt damage, put that many charge counters on Sun Droplet.
At the beginning of each upkeep, you may remove a charge counter from Sun Droplet. If you do, you gain 1 life.

Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.

Windborn Muse

Flying
Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Herald of War

Flying
Whenever Herald of War attacks, put a +1/+1 counter on it.
Angel spells and Human spells you cast cost {1} less to cast for each +1/+1 counter on Herald of War.

Spell Contortion

Multikicker {1}{U} (You may pay an additional {1}{U} any number of times as you cast this spell.)
Counter target spell unless its controller pays {2}. Draw a card for each time Spell Contortion was kicked.

Jhoira's Familiar

Flying
Historic spells you cast cost {1} less to cast. (Artifacts, legendaries, and Sagas are historic.)

Aura of Silence

Artifact and enchantment spells your opponents cast cost {2} more to cast.
Sacrifice Aura of Silence: Destroy target artifact or enchantment.

Broken Ambitions

Counter target spell unless its controller pays {X}. Clash with an opponent. If you win, that spell's controller mills four cards. (Each clashing player reveals the top card of their library, then puts that card on the top or bottom. A player wins if their card had a higher mana value.)

Brainwash

Enchant creature
Enchanted creature can't attack unless its controller pays {3}.

Complicate

Counter target spell unless its controller pays {3}.
Cycling {2}{U} ({2}{U}, Discard this card: Draw a card.)
When you cycle Complicate, you may counter target spell unless its controller pays {1}.

Heartstone

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Esior, Wardwing Familiar

Flying
Spells your opponents cast that target one or more commanders you control cost {3} more to cast.
Partner (You can have two commanders if both have partner.)

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Pendrell Mists

All creatures have "At the beginning of your upkeep, sacrifice this creature unless you pay {1}."

War Report

You gain life equal to the number of creatures on the battlefield plus the number of artifacts on the battlefield.

Grand Arbiter Augustin IV

White spells you cast cost {1} less to cast.
Blue spells you cast cost {1} less to cast.
Spells your opponents cast cost {1} more to cast.

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.

Foundry Inspector

Artifact spells you cast cost {1} less to cast.

Slow Motion

Enchant creature
At the beginning of the upkeep of enchanted creature's controller, that player sacrifices that creature unless they pay {2}.
When Slow Motion is put into a graveyard from the battlefield, return Slow Motion to its owner's hand.

Soul Conduit

{6}, {T}: Two target players exchange life totals.

Fluctuator

Cycling abilities you activate cost {2} less to activate.

Baird, Steward of Argive

Vigilance
Creatures can't attack you or planeswalkers you control unless their controller pays {1} for each of those creatures.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Defense Grid

Each spell costs {3} more to cast except during its controller's turn.

Chill

Etherium Sculptor

Convolute

Counter target spell unless its controller pays {4}.

Exotic Orchard

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

Lodestone Golem

Nonartifact spells cost {1} more to cast.

Lilting Refrain

At the beginning of your upkeep, you may put a verse counter on Lilting Refrain.
Sacrifice Lilting Refrain: Counter target spell unless its controller pays {X}, where X is the number of verse counters on Lilting Refrain.

Warden of Evos Isle

Flying
Creature spells with flying you cast cost {1} less to cast.

Decimator Web

{4}, {T}: Target opponent loses 2 life, gets a poison counter, then mills six cards.

Mana Tithe

Counter target spell unless its controller pays {1}.

Disruptive Student

{T}: Counter target spell unless its controller pays {1}.

Stonybrook Banneret

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Merfolk spells and Wizard spells you cast cost {1} less to cast.

Daze

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
Counter target spell unless its controller pays {1}.

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.

Magus of the Tabernacle

Orim's Prayer

Whenever one or more creatures attack you, you gain 1 life for each attacking creature.

Thorn of Amethyst

Jubilant Skybonder

Flying
Creatures you control with flying have "Spells your opponents cast that target this creature cost {2} more to cast."

Power Taint

Enchant enchantment
At the beginning of the upkeep of enchanted enchantment's controller, that player loses 2 life unless they pay {2}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Halimar Depths

Halimar Depths enters tapped.
When Halimar Depths enters, look at the top three cards of your library, then put them back in any order.
{T}: Add {U}.

Feroz's Ban

Mirrorworks

Whenever another nontoken artifact you control enters, you may pay {2}. If you do, create a token that's a copy of that artifact.

Callaphe, Beloved of the Sea

Callaphe's power is equal to your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
Creatures and enchantments you control have "Spells your opponents cast that target this permanent cost {1} more to cast."

Lunar Mystic

Whenever you cast an instant spell, you may pay {1}. If you do, draw a card.

Reliquary Tower

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

Smokestack

At the beginning of your upkeep, you may put a soot counter on Smokestack.
At the beginning of each player's upkeep, that player sacrifices a permanent of their choice for each soot counter on Smokestack.

Chronomantic Escape

Until your next turn, creatures can't attack you. Exile Chronomantic Escape with three time counters on it.
Suspend 3—{2}{W} (Rather than cast this card from your hand, you may pay {2}{W} 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.)

Venser's Journal

You have no maximum hand size.
At the beginning of your upkeep, you gain 1 life for each card in your hand.

Metalwork Colossus

This spell costs {X} less to cast, where X is the total mana value of noncreature artifacts you control.
Sacrifice two artifacts: Return Metalwork Colossus from your graveyard to your hand.

Calciform Pools

{T}: Add {C}.
{1}, {T}: Put a storage counter on Calciform Pools.
{1}, Remove X storage counters from Calciform Pools: Add X mana in any combination of {W} and/or {U}.

Island

Condescend

Counter target spell unless its controller pays {X}. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

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.

Erratic Portal

{1}, {T}: Return target creature to its owner's hand unless its controller pays {1}.

Kopala, Warden of Waves

Spells your opponents cast that target a Merfolk you control cost {2} more to cast.
Abilities your opponents activate that target a Merfolk you control cost {2} more to activate.

Blinkmoth Nexus

{T}: Add {C}.
{1}: Blinkmoth Nexus becomes a 1/1 Blinkmoth artifact creature with flying until end of turn. It's still a land.
{1}, {T}: Target Blinkmoth creature gets +1/+1 until end of turn.

Vivid Creek

Vivid Creek enters tapped with two charge counters on it.
{T}: Add {U}.
{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.

Offering to Asha

Counter target spell unless its controller pays {4}. You gain 4 life.

Cursecatcher

Sacrifice Cursecatcher: Counter target instant or sorcery spell unless its controller pays {1}.

Brine Seer

{2}{U}, {T}: Reveal any number of blue cards in your hand. Counter target spell unless its controller pays {1} for each card revealed this way.

Memory Crystal

Norn's Annex

({W/P} can be paid with either {W} or 2 life.)
Creatures can't attack you or planeswalkers you control unless their controller pays {W/P} for each of those creatures.

Glacial Fortress

Glacial Fortress enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Suppression Field

Activated abilities cost {2} more to activate unless they're mana abilities.

Plains

Disrupt

Counter target instant or sorcery spell unless its controller pays {1}.
Draw a card.