Gideon's Avenger

Whenever a creature an opponent controls becomes tapped, put a +1/+1 counter on Gideon's Avenger.

Icy Blast

Tap X target creatures.
Ferocious — If you control a creature with power 4 or greater, those creatures don't untap during their controllers' next untap steps.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Island

Githzerai Monk

Flash
Flying
Psychic Defense — When Githzerai Monk enters, tap all creatures you don't control.

Court Street Denizen

Whenever another white creature you control enters, tap target creature an opponent controls.

Azorius Guildmage

{2}{W}: Tap target creature.
{2}{U}: Counter target activated ability. (Mana abilities can't be targeted.)

Niveous Wisps

Target creature becomes white until end of turn. Tap that creature.
Draw a card.

Azorius Guildgate

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

Blinding Mage

Citadel Siege

As Citadel Siege enters, choose Khans or Dragons.
• Khans — At the beginning of combat on your turn, put two +1/+1 counters on target creature you control.
• Dragons — At the beginning of combat on each opponent's turn, tap target creature that player controls.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Downpour

Gadwick, the Wizened

When Gadwick, the Wizened enters, draw X cards.
Whenever you cast a blue spell, tap target nonland permanent an opponent controls.

Frostbridge Guard

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.)

Scepter of Dominance

Dreamshackle Geist

Flying
At the beginning of combat on your turn, choose up to one —
• Tap target creature.
• Target creature doesn't untap during its controller's next untap step.

Aetherize

Return all attacking creatures to their owner's hand.

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}

Lossarnach Captain

First strike
Whenever Lossarnach Captain or another Human you control enters, tap target creature an opponent controls.
At the beginning of your upkeep, create a 1/1 white Human Soldier creature token.

Boreal Shelf

Boreal Shelf enters tapped.
{T}: Add {W} or {U}.

Sunblast Angel

Flying
When Sunblast Angel enters, destroy all tapped creatures.

Niblis of Frost

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast an instant or sorcery spell, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Gideon's Lawkeeper

Feeling of Dread

Tap up to two target creatures.
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Idyllic Beachfront

({T}: Add {W} or {U}.)
Idyllic Beachfront enters tapped.

Time of Ice

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Tap target creature an opponent controls. It doesn't untap during its controller's untap step for as long as you control Time of Ice.
III — Return all tapped creatures to their owners' hands.

Rage of Winter

Tap target creature. It doesn't untap during its controller's next untap step. (Then exile this card. You may cast the creature later from exile.)

Queen of Ice

Whenever Queen of Ice deals combat damage to a creature, tap that creature. It doesn't untap during its controller's next untap step.

Queen of Ice // Rage of Winter

Floodpits Drowner

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

Blustersquall

Tap target creature you don't control.
Overload {3}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Ojutai Exemplars

Whenever you cast a noncreature spell, choose one —
• Tap target creature.
• Ojutai Exemplars gains first strike and lifelink until end of turn.
• Exile Ojutai Exemplars, then return it to the battlefield tapped under its owner's control.

Hylda's Crown of Winter

{1}, {T}: Tap target creature. This ability costs {1} less to activate during your turn.
{3}, Sacrifice Hylda's Crown of Winter: Draw a card for each tapped creature your opponents control.

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.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Verity Circle

Whenever a creature an opponent controls becomes tapped, if it isn't being declared as an attacker, you may draw a card.
{4}{U}: Tap target creature without flying.

Subjugator Angel

Flying
When Subjugator Angel enters, tap all creatures your opponents control.

Ballynock Trapper

{T}: Tap target creature.
Whenever you cast a white spell, you may untap Ballynock Trapper.

Split Up

Choose one —
• Destroy all tapped creatures.
• Destroy all untapped creatures.

Junk Winder

Affinity for tokens (This spell costs {1} less to cast for each token you control.)
Whenever a token you control enters, tap target nonland permanent an opponent controls. It doesn't untap during its controller's next untap step.

Borrowing 100,000 Arrows

Draw a card for each tapped creature target opponent controls.

Seized from Slumber

This spell costs {3} less to cast if it targets a tapped creature.
Destroy target creature.

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.)

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.

Solitary Sanctuary

When Solitary Sanctuary 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.

Command Tower

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

Theft of Dreams

Plunge into Winter

Tap up to one target creature. Scry 1, then draw a card.

Sentinel of the Eternal Watch

Vigilance (Attacking doesn't cause this creature to tap.)
At the beginning of combat on each opponent's turn, tap target creature that player controls.

Niblis of the Urn

Flying
Whenever Niblis of the Urn attacks, you may tap target creature.

Opposition

Tap an untapped creature you control: Tap target artifact, creature, or land.

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.)

Willbreaker

Whenever a creature an opponent controls becomes the target of a spell or ability you control, gain control of that creature for as long as you control Willbreaker.

Fear of Sleep Paralysis

Flying
Eerie — Whenever Fear of Sleep Paralysis 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.)

Hammers of Moradin

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Whenever Hammers of Moradin attacks, for each opponent, tap up to one target creature that player controls.

Arcane Signet

Chop Down

Destroy target creature with power 4 or greater. (Then exile this card. You may cast the creature later from exile.)

Giant Killer

Giant Killer // Chop Down

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.

Plains

Frost Titan

Whenever Frost Titan becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {2}.
Whenever Frost Titan enters or attacks, tap target permanent. It doesn't untap during its controller's next untap step.

Sleep

Tap all creatures target player controls. Those creatures don't untap during that player's next untap step.

Cone of Cold

Roll a d20.
1—9 | Tap all creatures your opponents control.
10—19 | Tap all creatures your opponents control. Those creatures don't untap during their controllers' next untap steps.
20 | Tap all creatures your opponents control. Those creatures don't untap during their controllers' next untap steps. Until your next turn, creatures your opponents control enter tapped.

Bond of Discipline

Tap all creatures your opponents control. Creatures you control gain lifelink until end of turn.

Tempest Caller

When Tempest Caller enters, tap all creatures target opponent controls.

Topplegeist

Flying
When Topplegeist enters, tap target creature an opponent controls.
Delirium — At the beginning of each opponent's upkeep, if there are four or more card types among cards in your graveyard, tap target creature that player controls.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.

Hithlain Knots

Tap target creature. Scry 1.
Draw a card.

Icewrought Sentry

Vigilance
Whenever Icewrought Sentry attacks, you may pay {1}{U}. When you do, tap target creature an opponent controls.
Whenever you tap an untapped creature an opponent controls, Icewrought Sentry gets +2/+1 until end of turn.

Propaganda

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

Eriette's Lullaby

Destroy target tapped creature. You gain 2 life.

Azorius Signet

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, Geist Avenger.

Sharae of Numbing Depths

When Sharae of Numbing Depths 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.