Brainstorm

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

Mountain

The Locust God

Flying
Whenever you draw a card, create a 1/1 blue and red Insect creature token with flying and haste.
{2}{U}{R}: Draw a card, then discard a card.
When The Locust God dies, return it to its owner's hand at the beginning of the next end step.

Steam Vents

({T}: Add {U} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Mirror Gallery

Fervor

Creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

End the Festivities

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

Cinder Pyromancer

{T}: This creature deals 1 damage to target player or planeswalker.
Whenever you cast a red spell, you may untap this creature.

Myriad Landscape

This land enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice this land: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Consider

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

Goblin Sharpshooter

This creature doesn't untap during your untap step.
Whenever a creature dies, untap this creature.
{T}: This creature deals 1 damage to any target.

Krenko, Mob Boss

{T}: Create X 1/1 red Goblin creature tokens, where X is the number of Goblins you control.

Alrund's Epiphany

Create two 1/1 blue Bird creature tokens with flying. Take an extra turn after this one. Exile Alrund's Epiphany.
Foretell {4}{U}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

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.

The Phasing of Zhalfir

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I, II — Another target nonland permanent phases out. It can't phase in for as long as you control this Saga.
III — Destroy all creatures. For each creature destroyed this way, its controller creates a 2/2 black Phyrexian creature token.

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Pink Horror

Coruscating Flames — Whenever you cast an instant or sorcery spell, this creature deals 2 damage to any target.
Split — When this creature dies, create two 2/2 blue and red Demon Horror creature tokens named Blue Horror with "Whenever you cast an instant or sorcery spell, this token deals 1 damage to any target."

Young Pyromancer

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

Island

Sulfur Falls

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

Izzet Signet

Polymorphist's Jest

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Dramatic Reversal

Untap all nonland permanents you control.

Counterspell

Inferno Titan

{R}: This creature gets +1/+0 until end of turn.
Whenever this creature enters or attacks, it deals 3 damage divided as you choose among one, two, or three targets.

Spark Double

You may have this creature enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Alchemist's Gambit

Cleave {4}{U}{U}{R} (You may cast this spell for its cleave cost. If you do, remove the words in square brackets.)
Take an extra turn after this one. During that turn, damage can't be prevented. [At the beginning of that turn's end step, you lose the game.]
Exile Alchemist's Gambit.

Cavalcade of Calamity

Whenever a creature you control with power 1 or less attacks, this enchantment deals 1 damage to the player or planeswalker that creature is attacking.

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

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 deals 2 damage to that permanent or player.

Niv-Mizzet, Parun

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

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.")

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Blazing Volley

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

Cascade Bluffs

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

Needle Drop

Needle Drop deals 1 damage to any target that was dealt damage this turn.
Draw a card.

Thermo-Alchemist

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

Zada's Commando

First strike
Cohort — {T}, Tap an untapped Ally you control: This creature deals 1 damage to target opponent or planeswalker.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Gorgon's Head

Equipped creature has deathtouch.
Equip {2}

Manabarbs

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

Tandem Lookout

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Tandem Lookout is paired with another creature, each of those creatures has "Whenever this creature deals damage to an opponent, draw a card."

Gelectrode

{T}: This creature deals 1 damage to any target.
Whenever you cast an instant or sorcery spell, you may untap this creature.

Seething Song

Sol Ring

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Izzet Boilerworks

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {U}{R}.

Exalted Flamer of Tzeentch

Sorcerous Inspiration — At the beginning of your upkeep, return an instant or sorcery card at random from your graveyard to your hand.
Fire of Tzeentch — Whenever you cast an instant or sorcery spell, this creature deals 1 damage to each opponent.

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Long-Term Plans

Search your library for a card, then shuffle and put that card third from the top.

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.

Electrostatic Field

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

Dual Shot

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

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Spitfire Lagac

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

Fellwar Stone

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

Wu Longbowman

{T}: This creature deals 1 damage to any target. Activate only during your turn, before attackers are declared.

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.

Arcane Signet

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

Command Tower

Caltrops

Whenever a creature attacks, this artifact deals 1 damage to it.

Kessig Flamebreather

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Goblin Chainwhirler

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

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.

Izzet Guildgate

This land enters tapped.
{T}: Add {U} or {R}.

Spikefield Cave

Spikefield Hazard

Spikefield Hazard deals 1 damage to any target. If a permanent dealt damage this way would die this turn, exile it instead.

Spikefield Hazard // Spikefield Cave

Negate

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.)

Training Center

This land enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Firebrand Archer

Illusionist's Bracers

Whenever an ability of equipped creature is activated, if it isn't a mana ability, copy that ability. You may choose new targets for the copy.
Equip {3}

Witch's Clinic

{T}: Add {C}.
{2}, {T}: Target commander gains lifelink until end of turn.

Mirror March

Whenever a nontoken creature you control enters, flip a coin until you lose a flip. For each flip you won, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

Curiosity

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

Ruby Medallion

Red spells you cast cost {1} less to cast.

Defiler of Instinct

First strike
As an additional cost to cast red permanent spells, you may pay 2 life. Those spells cost {R} less to cast if you paid life this way. This effect reduces only the amount of red mana you pay.
Whenever you cast a red permanent spell, this creature deals 1 damage to any target.