Counterspell

Aetherize

Return all attacking creatures to their owner's hand.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Lambholt Ravager

Whenever you cast a noncreature spell, Lambholt Ravager deals 2 damage to each opponent.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Lambholt Raconteur

Whenever you cast a noncreature spell, Lambholt Raconteur deals 1 damage to each opponent.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Lambholt Raconteur // Lambholt Ravager

Nettle Drone

Devoid (This card has no color.)
{T}: Nettle Drone deals 1 damage to each opponent.
Whenever you cast a colorless spell, untap Nettle Drone.

Goblin Chainwhirler

First strike
When Goblin Chainwhirler enters, it deals 1 damage to each opponent and each creature and planeswalker they control.

Tibalt, Rakish Instigator

Your opponents can't gain life.
−2: Create a 1/1 red Devil creature token with "When this creature dies, it deals 1 damage to any target."

Essence Capture

Counter target creature spell. Put a +1/+1 counter on up to one target creature you control.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Darksteel Plate

Indestructible
Equipped creature has indestructible.
Equip {2}

Flood of Recollection

Return target instant or sorcery card from your graveyard to your hand. Exile Flood of Recollection.

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Twinferno

Choose one —
• When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
• Target creature you control gains double strike until end of turn.

Circle of Flame

Whenever a creature without flying attacks you or a planeswalker you control, Circle of Flame deals 1 damage to that creature.

Expressive Iteration

Look at the top three cards of your library. Put one of them into your hand, put one of them on the bottom of your library, and exile one of them. You may play the exiled card this turn.

Hellrider

Haste
Whenever a creature you control attacks, Hellrider deals 1 damage to the player or planeswalker it's attacking.

Smoke Spirits' Aid

For each of up to X target creatures, create a red Aura enchantment token named Smoke Blessing attached to that creature. Those tokens have enchant creature and "When enchanted creature dies, it deals 1 damage to its controller and you create a Treasure token."

Seismic Wave

Seismic Wave deals 2 damage to any target and 1 damage to each nonartifact creature target opponent controls.

Staff of Nin

At the beginning of your upkeep, draw a card.
{T}: Staff of Nin deals 1 damage to any target.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Gut Shot

({R/P} can be paid with either {R} or 2 life.)
Gut Shot deals 1 damage to any target.

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Glaring Spotlight

Creatures your opponents control with hexproof can be the targets of spells and abilities you control as though they didn't have hexproof.
{3}, Sacrifice Glaring Spotlight: Creatures you control gain hexproof until end of turn and can't be blocked this turn.

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Rockslide Sorcerer

Whenever you cast an instant, sorcery, or Wizard spell, Rockslide Sorcerer deals 1 damage to any target.

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.

Dual Shot

Dual Shot deals 1 damage to each of up to two target creatures.

Ral, Storm Conduit

Whenever you cast or copy an instant or sorcery spell, Ral, Storm Conduit deals 1 damage to target opponent or planeswalker.
+2: Scry 1.
−2: When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

Gorgon Flail

Equipped creature gets +1/+1 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy that creature.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Corrupted Conscience

Enchant creature
You control enchanted creature.
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Ghyrson Starn, Kelermorph

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Three Autostubs — Whenever another source you control deals exactly 1 damage to a permanent or player, Ghyrson Starn, Kelermorph deals 2 damage to that permanent or player.

Tunneling Geopede

Landfall — Whenever a land you control enters, Tunneling Geopede deals 1 damage to each opponent.