Sleep

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

Fellwar Stone

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

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.

Talisman of Progress

{T}: Add {C}.
{T}: Add {W} or {U}. Talisman of Progress deals 1 damage to you.

Counterspell

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.

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.)

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

Minister of Impediments

({W/U} can be paid with either {W} or {U}.)
{T}: Tap target creature.

Opposition

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

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.

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.

Borrowing 100,000 Arrows

Draw a card for each tapped creature target opponent controls.

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.

Silver Myr

Arcane Signet

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

Azorius Signet

Court Street Denizen

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

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Plant Tadpoles

Tap X target creatures. They don't untap during their controllers' next untap steps. (Then exile this card. You may cast the creature later from exile.)

Illithid Harvester

Ceremorphosis — When Illithid Harvester enters, turn any number of target tapped nontoken creatures face down. They're 2/2 Horror creatures.

Illithid Harvester // Plant Tadpoles

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.

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.

Sol Ring

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.

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.

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.

Split Up

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