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.

Sol Ring

Azorius Signet

Thought Vessel

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

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.

Fellwar Stone

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

Snow-Covered Plains

Snow-Covered Island

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}

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.

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.

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.

Gideon's Lawkeeper

Downpour

Minister of Impediments

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

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.

Cryptic Command

Choose two —
• Counter target spell.
• Return target permanent to its owner's hand.
• Tap all creatures your opponents control.
• Draw a card.

Squall Drifter

Goldmeadow Harrier

Tempest Caller

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

Winter Moon

Players can't untap more than one nonbasic land during their untap steps.

Ghostly Prison

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

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.")

Sleep

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

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.

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.)

Plunge into Winter

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

Gideon's Avenger

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

Archon of Emeria

Flying
Each player can't cast more than one spell each turn.
Nonbasic lands your opponents control enter tapped.