Into the Roil

Kicker {1}{U} (You may pay an additional {1}{U} as you cast this spell.)
Return target nonland permanent to its owner's hand. If this spell was kicked, draw a card.

Firmament Sage

If it's neither day nor night, it becomes day as this creature enters.
Whenever day becomes night or night becomes day, draw a card.

Plains

Sunrise Cavalier

Trample, haste
If it's neither day nor night, it becomes day as this creature enters.
Whenever day becomes night or night becomes day, put a +1/+1 counter on target creature you control.

Frost Bite

Frost Bite deals 2 damage to target creature or planeswalker. If you control three or more snow permanents, it deals 3 damage instead.

Spikefield Cave

Spikefield Hazard

Spikefield Hazard deals 1 damage to any target. If a permanent dealt damage this way would die this turn, exile it instead.

Spikefield Hazard // Spikefield Cave

Snow-Covered Mountain

Fateful Absence

Destroy target creature or planeswalker. Its controller investigates. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Obsessive Astronomer

If it's neither day nor night, it becomes day as this creature enters.
Whenever day becomes night or night becomes day, discard up to two cards, then draw that many cards.

Sunstreak Phoenix

Flying
If it's neither day nor night, it becomes day as this creature enters.
Whenever day becomes night or night becomes day, you may pay {1}{R}. If you do, return this card from your graveyard to the battlefield tapped.

Play with Fire

Play with Fire deals 2 damage to any target. If a player is dealt damage this way, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Component Collector

If it's neither day nor night, it becomes day as this creature enters.
Whenever day becomes night or night becomes day, you may tap or untap target nonland permanent.

Vadrik, Astral Archmage

If it's neither day nor night, it becomes day as Vadrik enters.
Instant and sorcery spells you cast cost {X} less to cast, where X is Vadrik's power.
Whenever day becomes night or night becomes day, put a +1/+1 counter on Vadrik.

Brimstone Vandal

Menace (This creature can't be blocked except by two or more creatures.)
If it's neither day nor night, it becomes day as this creature enters.
Whenever day becomes night or night becomes day, this creature deals 1 damage to each opponent.

The Celestus

If it's neither day nor night, it becomes day as The Celestus enters.
{T}: Add one mana of any color.
{3}, {T}: If it's night, it becomes day. Otherwise, it becomes night. Activate only as a sorcery.
Whenever day becomes night or night becomes day, you gain 1 life. You may draw a card. If you do, discard a card.