Voldaren Stinger

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

Embodiment of Flame

Whenever a spell you control deals damage, put a flame counter on this creature.
{1}, Remove a flame counter from this creature: Exile the top card of your library. You may play that card this turn.

Flame Channeler

When a spell you control deals damage, transform this creature.

Flame Channeler // Embodiment of Flame

Ardent Elementalist

When this creature enters, return target instant or sorcery card from your graveyard to your hand.

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.

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.)

Moonrager's Slash

This spell costs {2} less to cast if it's night.
Moonrager's Slash deals 3 damage to any target.

Seize the Storm

Create a red Elemental creature token with trample and "This token's power and toughness are each equal to the number of instant and sorcery cards in your graveyard plus the number of cards with flashback you own in exile."
Flashback {6}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Falkenrath Perforator

Whenever this creature attacks, it deals 1 damage to defending player.

Festival Crasher

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

Thermo-Alchemist

Defender
{T}: This creature deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap this creature.

Cathartic Pyre

Choose one —
• Cathartic Pyre deals 3 damage to target creature or planeswalker.
• Discard up to two cards, then draw that many cards.

Spellrune Howler

Whenever you cast an instant or sorcery spell, this creature gets +2/+2 until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Spellrune Painter

Whenever you cast an instant or sorcery spell, this creature gets +1/+1 until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Spellrune Painter // Spellrune Howler

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.