Maybe

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.)

Easy cut

Burning Earth

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

Twin Bolt

Twin Bolt deals 2 damage divided as you choose among one or two targets.

Invocation of the Founders

Whenever you cast an instant or sorcery spell from your hand, you may copy that spell. You may choose new targets for the copy.

Invasion of Arcavios

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, search your library, graveyard, and/or outside the game for an instant or sorcery card you own, reveal it, and put it into your hand. If you search your library this way, shuffle.

Invasion of Arcavios // Invocation of the Founders

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.

Shower of Sparks

Shower of Sparks deals 1 damage to target creature and 1 damage to target player or planeswalker.

Gifts Ungiven

Search your library for up to four cards with different names and reveal them. Target opponent chooses two of those cards. Put the chosen cards into your graveyard and the rest into your hand. Then shuffle.

Aether Sting

Whenever an opponent casts a creature spell, this enchantment deals 1 damage to that player.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Jwari Ruins

Jwari Disruption

Counter target spell unless its controller pays {1}.

Jwari Disruption // Jwari Ruins

Ral, Leyline Prodigy

Ral enters with an additional loyalty counter on him for each instant and sorcery spell you've cast this turn.
+1: Until your next turn, instant and sorcery spells you cast cost {1} less to cast.
−2: Ral deals 2 damage divided as you choose among one or two targets. Draw a card if you control a blue permanent other than Ral.
−8: Exile the top eight cards of your library. You may cast instant and sorcery spells from among them this turn without paying their mana costs.

Ral, Monsoon Mage

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell during your turn, flip a coin. If you lose the flip, Ral deals 1 damage to you. If you win the flip, you may exile Ral. If you do, return him to the battlefield transformed under his owner's control.

Ral, Monsoon Mage // Ral, Leyline Prodigy

End the Festivities

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

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.

Repercussion

Whenever a creature is dealt damage, this enchantment deals that much damage to that creature's controller.

Have

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.)

Reliquary Tower

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

The Red Terror

Advanced Species — Whenever a red source you control deals damage to one or more permanents and/or players, put a +1/+1 counter on The Red Terror.

Stormcarved Coast

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

Circular Logic

Counter target spell unless its controller pays {1} for each card in your graveyard.
Madness {U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Chandra's Spitfire

Flying
Whenever an opponent is dealt noncombat damage, this creature gets +3/+0 until end of turn.

Dual Shot

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

Thrill of Possibility

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

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, this creature deals 1 damage to that player.

Scalding Viper // Steam Clean

Lavaglide Pathway

Riverglide Pathway

Riverglide Pathway // Lavaglide Pathway

Thought Scour

Target player mills two cards.
Draw a card.

Barrage of Boulders

Barrage of Boulders deals 1 damage to each creature you don't control.
Ferocious — If you control a creature with power 4 or greater, creatures can't block this turn.

Etching of Kumano

Haste
If a creature dealt damage this turn by a source you controlled would die, exile it instead.

Kumano Faces Kakkazan

(As this Saga enters and after your draw step, add a lore counter.)
I — This Saga deals 1 damage to each opponent and each planeswalker they control.
II — When you next cast a creature spell this turn, that creature enters with an additional +1/+1 counter on it.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Kumano Faces Kakkazan // Etching of Kumano

Brainstorm

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

Soporific Springs

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {U}.

Sink into Stupor

Return target spell or nonland permanent an opponent controls to its owner's hand.

Sink into Stupor // Soporific Springs

Dive Down

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Firebrand Archer

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

Eroded Canyon

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

Cast into the Fire

Choose one —
• Cast into the Fire deals 1 damage to each of up to two target creatures.
• Exile target artifact.

Kessig Flamebreather

Take into Custody

Tap target creature. It doesn't untap during its controller's next untap step.

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.")

Sorcerer Class

(Gain the next level as a sorcery to add its ability.)
When this Class enters, draw two cards, then discard two cards.
{U}{R}: Level 2
Creatures you control have "{T}: Add {U} or {R}. Spend this mana only to cast an instant or sorcery spell or to gain a Class level."
{3}{U}{R}: Level 3
Whenever you cast an instant or sorcery spell, that spell deals damage to each opponent equal to the number of instant and sorcery spells you've cast this turn.

Spirebluff Canal

This land enters tapped unless you control two or fewer other lands.
{T}: Add {U} or {R}.

Mage Siege

Create a 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent."

Lindblum, Industrial Regency

Lindblum, Industrial Regency // Mage Siege

Tectonic Hazard

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

Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Powerbalance

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, you may cast that card without paying its mana cost if the two spells have the same mana value.

Dance with Calamity

Shuffle your library. As many times as you choose, you may exile the top card of your library. If the total mana value of the cards exiled this way is 13 or less, you may cast any number of spells from among those cards without paying their mana costs.

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.

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}.

Razorkin Needlehead

This creature has first strike during your turn.
Whenever an opponent draws a card, this creature deals 1 damage to them.

Swiftwater Cliffs

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {U} or {R}.

Geistflame

Geistflame deals 1 damage to any target.
Flashback {3}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Blazing Volley

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

Island

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, this creature deals that much damage to target creature or planeswalker that player controls.

Forktail Sweep

Forktail Sweep deals 1 damage to each creature you don't control. (Then exile this card. You may cast the creature later from exile.)

Fang Dragon

Fang Dragon // Forktail Sweep

Shore Up

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Erebor Flamesmith

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

Rampaging Ferocidon

Menace
Players can't gain life.
Whenever another creature enters, this creature deals 1 damage to that creature's controller.

Electrolyze

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

Whirlwind Denial

For each spell and ability your opponents control, counter it unless its controller pays {4}.

Ash Barrens

{T}: Add {C}.
Basic landcycling {1} ({1}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Barbflare Gremlin

First strike, haste
Whenever a player taps a land for mana, if this creature is tapped, that player adds one mana of any type that land produced. Then that land deals 1 damage to that player.

Sigil of Sleep

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

The Great Work

(As this Saga enters and after your draw step, add a lore counter.)
I — This Saga 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 this Saga, 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

Terramorphic Expanse

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Getting

Shivan Gorge

{T}: Add {C}.
{2}{R}, {T}: Shivan Gorge deals 1 damage to each opponent.

Negate

Hard cut

Valakut Exploration

Landfall — Whenever a land you control enters, exile the top card of your library. You may play that card for as long as it remains exiled.
At the beginning of your end step, if there are cards exiled with this enchantment, put them into their owner's graveyard, then this enchantment deals that much damage to each opponent.

Curiosity

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

Mountain

Disrupt

Counter target instant or sorcery spell unless its controller pays {1}.
Draw a card.

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

Temple of Epiphany

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {R}.

Fiery Islet

{T}, Pay 1 life: Add {U} or {R}.
{1}, {T}, Sacrifice this land: Draw a card.

Storm-Kiln Artist

This creature gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token.

Harnfel, Horn of Bounty

Discard a card: Exile the top two cards of your library. You may play those cards this turn.

Birgi, God of Storytelling

Whenever you cast a spell, add {R}. Until end of turn, you don't lose this mana as steps and phases end.
Creatures you control can boast twice during each of your turns rather than once.

Birgi, God of Storytelling // Harnfel, Horn of Bounty

Divert

Change the target of target spell with a single target unless that spell's controller pays {2}.

Torbran, Thane of Red Fell

If a red source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

Gleeful Arsonist

Whenever an opponent casts a noncreature spell, this creature 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.)

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.

Scorching Winds

Cast this spell only during the declare attackers step and only if you've been attacked this step.
Scorching Winds deals 1 damage to each attacking creature.

Reverberate

Copy target instant or sorcery spell. You may choose new targets for the copy.

Mana Leak

Counter target spell unless its controller pays {3}.

Slip Out the Back

Put a +1/+1 counter on target creature. It phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

Divert Disaster

Counter target spell unless its controller pays {2}. If they do, you create a Lander token. (It's an artifact with "{2}, {T}, Sacrifice this token: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.")

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.

Counterbalance

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, counter that spell if it has the same mana value as the revealed card.