Prismari Apprentice

Magecraft — Whenever you cast or copy an instant or sorcery spell, Prismari Apprentice can't be blocked this turn. If that spell has mana value 5 or greater, put a +1/+1 counter on Prismari Apprentice.

Snow Day

Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.
Draw two cards, then discard a card.

Frost Trickster

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

Maelstrom Muse

Flying
Whenever Maelstrom Muse attacks, the next instant or sorcery spell you cast this turn costs {X} less to cast, where X is Maelstrom Muse's power as this ability resolves.

Spectacle Mage

Flying
Instant and sorcery spells you cast with mana value 5 or greater cost {1} less to cast.

Prismari Pledgemage

Defender
Magecraft — Whenever you cast or copy an instant or sorcery spell, Prismari Pledgemage can attack this turn as though it didn't have defender.