Festival Crasher

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

Ancestral Anger

Target creature gains trample and gets +X/+0 until end of turn, where X is 1 plus the number of cards named Ancestral Anger in your graveyard. (A creature with trample can deal excess combat damage to the player or planeswalker it's attacking.)
Draw a card.

Lava Dart

Lava Dart deals 1 damage to any target.
Flashback—Sacrifice a Mountain. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Manamorphose

Add two mana in any combination of colors.
Draw a card.

Fireblast

You may sacrifice two Mountains rather than pay this spell's mana cost.
Fireblast deals 4 damage to any target.

Temur Battle Rage

Target creature gains double strike until end of turn.
Ferocious — That creature also gains trample until end of turn if you control a creature with power 4 or greater.

Kiln Fiend

Whenever you cast an instant or sorcery spell, Kiln Fiend gets +3/+0 until end of turn.

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

Mutagenic Growth

({G/P} can be paid with either {G} or 2 life.)
Target creature gets +2/+2 until end of turn.

Mountain

Brute Force

Target creature gets +3/+3 until end of turn.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Fire Urchin

Trample
Whenever you cast an instant or sorcery spell, Fire Urchin gets +1/+0 until end of turn.