Thud

As an additional cost to cast this spell, sacrifice a creature.
Thud deals damage equal to the sacrificed creature's power to any target.

Satyr Firedancer

Whenever an instant or sorcery spell you control deals damage to an opponent, Satyr Firedancer deals that much damage to target creature that player controls.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Grim Lavamancer

{R}, {T}, Exile two cards from your graveyard: Grim Lavamancer deals 2 damage to any target.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Dreadhorde Arcanist

Trample
Whenever Dreadhorde Arcanist attacks, you may cast target instant or sorcery card with mana value less than or equal to Dreadhorde Arcanist's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Abbot of Keral Keep

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Abbot of Keral Keep enters, exile the top card of your library. Until end of turn, you may play that card.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Mountain

Skewer the Critics

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Skewer the Critics deals 3 damage to any target.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Monastery Swiftspear

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 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.