Call the Coppercoats

Strive — This spell costs {1}{W} more to cast for each target beyond the first.
Choose any number of target opponents. Create X 1/1 white Human Soldier creature tokens, where X is the number of creatures those opponents control.

Starstorm

Starstorm deals X damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

Taii Wakeen, Perfect Shot

Whenever a source you control deals noncombat damage to a creature equal to that creature's toughness, draw a card.
{X}, {T}: If a source you control would deal noncombat damage to a permanent or player this turn, it deals that much damage plus X instead.

Seismic Shudder

Seismic Shudder deals 1 damage to each creature without flying.

Fallen Ferromancer

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{1}{R}, {T}: Fallen Ferromancer deals 1 damage to any target.

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Cinderclasm

Kicker {R} (You may pay an additional {R} as you cast this spell.)
Cinderclasm deals 1 damage to each creature. If it was kicked, it deals 2 damage to each creature instead.

Impact Resonance

Impact Resonance deals X damage divided as you choose among any number of target creatures, where X is the greatest amount of damage dealt by a source to a permanent or player this turn.

Pyrokinesis

You may exile a red card from your hand rather than pay this spell's mana cost.
Pyrokinesis deals 4 damage divided as you choose among any number of target creatures.

Arcbond

Choose target creature. Whenever that creature is dealt damage this turn, it deals that much damage to each other creature and each player.

Wild Magic Surge

Destroy target permanent an opponent controls. Its controller reveals cards from the top of their library until they reveal a permanent card that shares a card type with that permanent. They put that card onto the battlefield and the rest on the bottom of their library in a random order.

Comeuppance

Prevent all damage that would be dealt to you and planeswalkers you control this turn by sources you don't control. If damage from a creature source is prevented this way, Comeuppance deals that much damage to that creature. If damage from a noncreature source is prevented this way, Comeuppance deals that much damage to the source's controller.

Cast into the Fire

Choose one —
• Cast into the Fire deals 1 damage to each of up to two target creatures.
• Exile target artifact.

Spikefield Cave

Spikefield Cave enters the battlefield tapped.
{T}: Add {R}.

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

Your Temple Is Under Attack

Choose one —
• Pray for Protection — Creatures you control gain indestructible until end of turn.
• Strike a Deal — You and target opponent each draw two cards.

Heartflame Slash

Heartflame Slash deals 3 damage to any target. (Then exile this card. You may cast the creature later from exile.)

Heartflame Duelist

Instant and sorcery spells you control have lifelink.

Heartflame Duelist // Heartflame Slash

Make a Stand

Creatures you control get +1/+0 and gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Neheb, the Eternal

Afflict 3 (Whenever this creature becomes blocked, defending player loses 3 life.)
At the beginning of your postcombat main phase, add {R} for each 1 life your opponents have lost this turn.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Rootborn Defenses

Populate. Creatures you control gain indestructible until end of turn. (To populate, create a token that's a copy of a creature token you control.)

Dualcaster Mage

Flash
When Dualcaster Mage enters the battlefield, copy target instant or sorcery spell. You may choose new targets for the copy.

Shake the Foundations

Shake the Foundations deals 1 damage to each creature without flying.
Draw a card.