Obsessive Astronomer

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

Festival Crasher

Whenever you cast an instant or sorcery spell, Festival Crasher gets +2/+0 until end of turn.

Sunstreak Phoenix

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

Falkenrath Perforator

Whenever Falkenrath Perforator attacks, it deals 1 damage to defending player.

Mountain

Burn Down the House

Choose one —
• Burn Down the House deals 5 damage to each creature and each planeswalker.
• Create three 1/1 red Devil creature tokens with "When this creature dies, it deals 1 damage to any target." They gain haste until end of turn.

Thriving Bluff

Thriving Bluff enters tapped. As it enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Purifying Dragon

Flying
Whenever Purifying Dragon attacks, it deals 1 damage to target creature defending player controls. If that creature is a Zombie, Purifying Dragon deals 2 damage to it instead.

Harvesttide Assailant

Trample
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Harvesttide Infiltrator

Trample
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Harvesttide Infiltrator // Harvesttide Assailant

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.)

Voldaren Stinger

Voldaren Stinger has first strike as long as it's attacking.
{2}{R}: Voldaren Stinger gets +2/+0 until end of turn.

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 Brimstone Vandal enters.
Whenever day becomes night or night becomes day, Brimstone Vandal deals 1 damage to each opponent.

Lambholt Harrier

{3}{R}: Target creature can't block this turn.

Lunar Frenzy

Target creature you control gets +X/+0 and gains first strike and trample until end of turn.