Collateral Damage

As an additional cost to cast this spell, sacrifice a creature.
Collateral Damage deals 3 damage to any target.

Harsh Mentor

Whenever an opponent activates an ability of an artifact, creature, or land on the battlefield, if it isn't a mana ability, Harsh Mentor deals 2 damage to that player.

Magma Jet

Magma Jet deals 2 damage to any target. Scry 2.

Monastery Swiftspear

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Ghitu Lavarunner

As long as there are two or more instant and/or sorcery cards in your graveyard, Ghitu Lavarunner gets +1/+0 and has haste.

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.

Rakdos Cackler

Unleash (You may have this creature enter with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)

Burning-Tree Emissary

When Burning-Tree Emissary enters, add {R}{G}.

Risk Factor

Target opponent may have Risk Factor deal 4 damage to them. If that player doesn't, you draw three cards.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Kari Zev, Skyship Raider

First strike, menace
Whenever Kari Zev, Skyship Raider attacks, create Ragavan, a legendary 2/1 red Monkey creature token. Ragavan enters tapped and attacking. Exile that token at end of combat.

Shock

Burst Lightning

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Burst Lightning deals 2 damage to any target. If this spell was kicked, it deals 4 damage instead.

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.

Kessig Flamebreather

Whenever you cast a noncreature spell, Kessig Flamebreather deals 1 damage to each opponent.

Frenzied Goblin

Whenever Frenzied Goblin attacks, you may pay {R}. If you do, target creature can't block this turn.

Gut, True Soul Zealot

Whenever you attack, you may sacrifice another creature or an artifact. If you do, create a 4/1 black Skeleton creature token with menace that's tapped and attacking. (It can't be blocked except by two or more creatures.)
Choose a Background (You can have a Background as a second commander.)

Fireblast

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

Ahn-Crop Crasher

Haste (This creature can attack and {T} as soon as it comes under your control.)
You may exert Ahn-Crop Crasher as it attacks. When you do, target creature can't block this turn. (An exerted creature won't untap during your next untap step.)

Rift Bolt

Rift Bolt deals 3 damage to any target.
Suspend 1—{R} (Rather than cast this card from your hand, you may pay {R} and exile it with a time counter on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Sulfuric Vortex

At the beginning of each player's upkeep, Sulfuric Vortex deals 2 damage to that player.
If a player would gain life, that player gains no life instead.

Wild Slash

Ferocious — If you control a creature with power 4 or greater, damage can't be prevented this turn.
Wild Slash deals 2 damage to any target.

Earthshaker Khenra

Haste
When Earthshaker Khenra enters, target creature with power less than or equal to Earthshaker Khenra's power can't block this turn.
Eternalize {4}{R}{R} ({4}{R}{R}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a 4/4 black Zombie Jackal Warrior with no mana cost. Eternalize only as a sorcery.)

Seal of Fire

Sacrifice Seal of Fire: It deals 2 damage to any target.

Hazoret the Fervent

Indestructible, haste
Hazoret the Fervent can't attack or block unless you have one or fewer cards in hand.
{2}{R}, Discard a card: Hazoret deals 2 damage to each opponent.

Lightning Strike

Lightning Strike deals 3 damage to any target.

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.)

Bomat Courier

Haste
Whenever Bomat Courier attacks, exile the top card of your library face down. (You can't look at it.)
{R}, Discard your hand, Sacrifice Bomat Courier: Put all cards exiled with Bomat Courier into their owners' hands.

Shard Volley

As an additional cost to cast this spell, sacrifice a land.
Shard Volley deals 3 damage to any target.

Viashino Pyromancer

When Viashino Pyromancer enters, it deals 2 damage to target player or planeswalker.

Light Up the Stage

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Eidolon of the Great Revel

Whenever a player casts a spell with mana value 3 or less, Eidolon of the Great Revel deals 2 damage to that player.

Goblin Guide

Haste
Whenever Goblin Guide attacks, defending player reveals the top card of their library. If it's a land card, that player puts it into their hand.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Searing Spear

Searing Spear deals 3 damage to any target.

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.

Goblin Glory Chaser

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
As long as Goblin Glory Chaser is renowned, it has menace. (It can't be blocked except by two or more creatures.)

Tarfire

Zurgo Bellstriker

Zurgo Bellstriker can't block creatures with power 2 or greater.
Dash {1}{R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Soul-Scar Mage

Prowess
If a source you control would deal noncombat damage to a creature an opponent controls, put that many -1/-1 counters on that creature instead.