Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet, Parun deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Razorkin Needlehead

Razorkin Needlehead has first strike during your turn.
Whenever an opponent draws a card, Razorkin Needlehead deals 1 damage to them.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

End the Festivities

End the Festivities deals 1 damage to each opponent and each creature and planeswalker they control.

Gorgon's Head

Equipped creature has deathtouch.
Equip {2}

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Mountain

Command Tower

Giggling Skitterspike

Indestructible
Whenever Giggling Skitterspike attacks, blocks, or becomes the target of a spell, it deals damage equal to its power to each opponent.
{5}: Monstrosity 5. (If this creature isn't monstrous, put five +1/+1 counters on it and it becomes monstrous.)

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Counterspell

Mizzix's Mastery

Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery.
Overload {5}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Kessig Flamebreather

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

Caltrops

Whenever a creature attacks, Caltrops deals 1 damage to it.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Electrickery

Electrickery deals 1 damage to target creature you don't control.
Overload {1}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Basilisk Collar

Equipped creature has deathtouch and lifelink.
Equip {2}

Playful Shove

Playful Shove deals 1 damage to any target.
Draw a card.

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.

Cascade Bluffs

{T}: Add {C}.
{U/R}, {T}: Add {U}{U}, {U}{R}, or {R}{R}.

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Song of Totentanz

Create X 1/1 black Rat creature tokens with "This creature can't block." Creatures you control gain haste until end of turn.

Electrostatic Field

Defender
Whenever you cast an instant or sorcery spell, Electrostatic Field deals 1 damage to each opponent.

Roiling Vortex

At the beginning of each player's upkeep, Roiling Vortex deals 1 damage to them.
Whenever a player casts a spell, if no mana was spent to cast that spell, Roiling Vortex deals 5 damage to that player.
{R}: Your opponents can't gain life this turn.

Invert Polarity

Choose target spell, then flip a coin. If you win the flip, gain control of that spell and you may choose new targets for it. If you lose the flip, counter that spell.

Erebor Flamesmith

Whenever you cast an instant or sorcery spell, Erebor Flamesmith deals 1 damage to each opponent.

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Island

Strix Serenade

Counter target artifact, creature, or planeswalker spell. Its controller creates a 2/2 blue Bird creature token with flying.

Case of the Ransacked Lab

Instant and sorcery spells you cast cost {1} less to cast.
To solve — You've cast four or more instant and sorcery spells this turn. (If unsolved, solve at the beginning of your end step.)
Solved — Whenever you cast an instant or sorcery spell, draw a card.

Archmage Emeritus

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

Steam Clean

Return target nonland permanent to its owner's hand. (Then exile this card. You may cast the creature later from exile.)

Scalding Viper

Whenever an opponent casts a spell with mana value 3 or less, Scalding Viper deals 1 damage to that player.

Scalding Viper // Steam Clean

Smash to Dust

Choose one —
• Destroy target artifact.
• Destroy target creature with defender.
• Smash to Dust deals 1 damage to each creature your opponents control.

Isochron Scepter

Imprint — When Isochron Scepter enters, you may exile an instant card with mana value 2 or less from your hand.
{2}, {T}: You may copy the exiled card. If you do, you may cast the copy without paying its mana cost.

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.

Ophidian Eye

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Grapeshot

Grapeshot deals 1 damage to any target.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Frostboil Snarl

As Frostboil Snarl enters, you may reveal an Island or Mountain card from your hand. If you don't, Frostboil Snarl enters tapped.
{T}: Add {U} or {R}.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Izzet Signet

Untimely Malfunction

Choose one —
• Destroy target artifact.
• Change the target of target spell or ability with a single target.
• One or two target creatures can't block this turn.

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.

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.

Gleeful Arsonist

Whenever an opponent casts a noncreature spell, Gleeful Arsonist deals damage equal to its power to that player.
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

The Great Work

(As this Saga enters and after your draw step, add a lore counter.)
I — The Great Work deals 3 damage to target opponent and each creature they control.
II — Create three Treasure tokens.
III — Until end of turn, you may cast instant and sorcery spells from any graveyard. If a spell cast this way would be put into a graveyard, exile it instead. Exile The Great Work, then return it to the battlefield (front face up).

Urabrask

First strike
Whenever you cast an instant or sorcery spell, Urabrask deals 1 damage to target opponent. Add {R}.
{R}: Exile Urabrask, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery and only if you've cast three or more instant and/or sorcery spells this turn.

Urabrask // The Great Work

Jeska's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Add {R} for each card in target opponent's hand.
• Exile the top three cards of your library. You may play them this turn.

Exotic Orchard

Third Path Iconoclast

Whenever you cast a noncreature spell, create a 1/1 colorless Soldier artifact creature token.

Electrolyze

Electrolyze deals 2 damage divided as you choose among one or two targets.
Draw a card.

Tectonic Hazard

Tectonic Hazard deals 1 damage to each opponent and each creature they control.

Firebrand Archer

Whenever you cast a noncreature spell, Firebrand Archer deals 1 damage to each opponent.

Chandra's Incinerator

This spell costs {X} less to cast, where X is the total amount of noncombat damage dealt to your opponents this turn.
Trample
Whenever a source you control deals noncombat damage to an opponent, Chandra's Incinerator deals that much damage to target creature or planeswalker that player controls.

Manabarbs

Whenever a player taps a land for mana, Manabarbs deals 1 damage to that player.

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.")

Saheeli Rai

+1: Scry 1. Saheeli Rai deals 1 damage to each opponent.
−2: Create a token that's a copy of target artifact or creature you control, except it's an artifact in addition to its other types. That token gains haste. Exile it at the beginning of the next end step.
−7: Search your library for up to three artifact cards with different names, put them onto the battlefield, then shuffle.

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Eroded Canyon

Eroded Canyon enters tapped.
When Eroded Canyon enters, it deals 1 damage to target opponent.
{T}: Add {U} or {R}.

Coruscation Mage

Offspring {2} (You may pay an additional {2} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Treasure Cruise

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Draw three cards.

Niv-Mizzet, Visionary

Flying
You have no maximum hand size.
Whenever a source you control deals noncombat damage to an opponent, you draw that many cards.

Sigil of Sleep

Enchant creature
Whenever enchanted creature deals damage to a player, return target creature that player controls to its owner's hand.

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Thermo-Alchemist

Defender
{T}: Thermo-Alchemist deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap Thermo-Alchemist.

Impact Tremors

Whenever a creature you control enters, Impact Tremors deals 1 damage to each opponent.

Niv-Mizzet, the Firemind

Flying
Whenever you draw a card, Niv-Mizzet, the Firemind deals 1 damage to any target.
{T}: Draw a card.

Blazing Volley

Blazing Volley deals 1 damage to each creature your opponents control.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Quicksilver Dagger

Enchant creature
Enchanted creature has "{T}: This creature deals 1 damage to target player or planeswalker. You draw a card."

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Stormcarved Coast

Stormcarved Coast enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.

Unruly Catapult

Defender
{T}: Unruly Catapult deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap Unruly Catapult.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.