Have

Rush of Ice

Tap target creature. It doesn't untap during its controller's next untap step.
Awaken 3—{4}{U} (If you cast this spell for {4}{U}, also put three +1/+1 counters on target land you control and it becomes a 0/0 Elemental creature with haste. It's still a land.)

Invisibility

Enchant creature
Enchanted creature can't be blocked except by Walls.

Deliberate

Chilling Grasp

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.
Madness {3}{U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Thassa's Ire

{3}{U}: You may tap or untap target creature.

Containment Membrane

Surge {U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Enchant creature
Enchanted creature doesn't untap during its controller's untap step.

Merfolk Trickster

Flash
When this creature enters, tap target creature an opponent controls. It loses all abilities until end of turn.

Slither Blade

Retraction Helix

Until end of turn, target creature gains "{T}: Return target nonland permanent to its owner's hand."

Select for Inspection

Return target tapped creature to its owner's hand. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Frost Breath

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Ice Over

Enchant artifact or creature
Enchanted permanent doesn't untap during its controller's untap step.

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 this Saga.
III — Return all tapped creatures to their owners' hands.

Hubris

Return target creature and all Auras attached to it to their owners' hands.

Stitched Mangler

This creature enters tapped.
When this creature enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Stasis

Players skip their untap steps.
At the beginning of your upkeep, sacrifice this enchantment unless you pay {U}.

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Galestrike

Return target tapped creature to its owner's hand.
Draw a card.

Unsummon

Return target creature to its owner's hand.

Take into Custody

Tap target creature. It doesn't untap during its controller's next untap step.

Wall of Frost

Defender
Whenever this creature blocks a creature, that creature doesn't untap during its controller's next untap step.

Ice Cage

Enchant creature
Enchanted creature can't attack or block, and its activated abilities can't be activated.
When enchanted creature becomes the target of a spell or ability, destroy this Aura.

Eternity Snare

Enchant creature
When this Aura enters, draw a card.
Enchanted creature doesn't untap during its controller's untap step.

Island

Frost Lynx

When this creature enters, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Gainsay

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 this creature 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

Ichthyomorphosis

Enchant creature
Enchanted creature loses all abilities and is a blue Fish with base power and toughness 0/1.

Inaction Injunction

Detain target creature an opponent controls. (Until your next turn, that creature can't attack or block and its activated abilities can't be activated.)
Draw a card.

Winter Orb

As long as this artifact is untapped, players can't untap more than one land during their untap steps.

Threnody Singer

Flash
Flying
When this creature enters, target creature an opponent controls gets -X/-0 until end of turn, where X is your devotion to blue. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Saw It Coming

Counter target spell.
Foretell {1}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)