Hand of Emrakul

You may sacrifice four Eldrazi Spawn rather than pay this spell's mana cost.
Annihilator 1 (Whenever this creature attacks, defending player sacrifices a permanent of their choice.)

Ricochet Trap

If an opponent cast a blue spell this turn, you may pay {R} rather than pay this spell's mana cost.
Change the target of target spell with a single target.

Spinning Darkness

You may exile the top three black cards of your graveyard rather than pay this spell's mana cost.
Spinning Darkness deals 3 damage to target nonblack creature. You gain 3 life.

Refreshing Rain

If an opponent controls a Swamp and you control a Forest, you may cast this spell without paying its mana cost.
Target player gains 6 life.

Pyrokinesis

You may exile a red card from your hand rather than pay this spell's mana cost.
Pyrokinesis deals 4 damage divided as you choose among any number of target creatures.

Sprouting Vines

Search your library for a basic land card, reveal that card, put it into your hand, then shuffle.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Soul Spike

You may exile two black cards from your hand rather than pay this spell's mana cost.
Soul Spike deals 4 damage to any target and you gain 4 life.

Mistvein Borderpost

You may pay {1} and return a basic land you control to its owner's hand rather than pay this spell's mana cost.
Mistvein Borderpost enters tapped.
{T}: Add {U} or {B}.

Nemesis Trap

If a white creature is attacking, you may pay {B}{B} rather than pay this spell's mana cost.
Exile target attacking creature. Create a token that's a copy of that creature. Exile it at the beginning of the next end step.

Sunscour

You may exile two white cards from your hand rather than pay this spell's mana cost.
Destroy all creatures.

Mind Swords

If you control a Swamp, you may sacrifice a creature rather than pay this spell's mana cost.
Each player exiles two cards from their hand.

Fury of the Horde

You may exile two red cards from your hand rather than pay this spell's mana cost.
Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Mogg Salvage

If an opponent controls an Island and you control a Mountain, you may cast this spell without paying its mana cost.
Destroy target artifact.

Skyshroud Cutter

If you control a Forest, rather than pay this spell's mana cost, you may have each other player gain 5 life.

Slingbow Trap

If a black creature with flying is attacking, you may pay {G} rather than pay this spell's mana cost.
Destroy target attacking creature with flying.

Sephara, Sky's Blade

You may pay {W} and tap four untapped creatures you control with flying rather than pay this spell's mana cost.
Flying, lifelink
Other creatures you control with flying have indestructible. (Damage and effects that say "destroy" don't destroy them.)

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.)

Thwart

You may return three Islands you control to their owner's hand rather than pay this spell's mana cost.
Counter target spell.

Refraction Trap

If an opponent cast a red instant or sorcery spell this turn, you may pay {W} rather than pay this spell's mana cost.
Prevent the next 3 damage that a source of your choice would deal to you and/or permanents you control this turn. If damage is prevented this way, Refraction Trap deals that much damage to any target.

Blazing Shoal

You may exile a red card with mana value X from your hand rather than pay this spell's mana cost.
Target creature gets +X/+0 until end of turn.

Wildfield Borderpost

You may pay {1} and return a basic land you control to its owner's hand rather than pay this spell's mana cost.
Wildfield Borderpost enters tapped.
{T}: Add {G} or {W}.

Ignite Memories

Target player reveals a card at random from their hand. Ignite Memories deals damage to that player equal to that card's mana value.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Diabolic Tutor

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

Archive Trap

If an opponent searched their library this turn, you may pay {0} rather than pay this spell's mana cost.
Target opponent mills thirteen cards.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Reverent Silence

If you control a Forest, rather than pay this spell's mana cost, you may have each other player gain 6 life.
Destroy all enchantments.

Bringer of the Green Dawn

You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost.
Trample
At the beginning of your upkeep, you may create a 3/3 green Beast creature token.

Whirlwind of Thought

Whenever you cast a noncreature spell, draw a card.

Allosaurus Rider

You may exile two green cards from your hand rather than pay this spell's mana cost.
Allosaurus Rider's power and toughness are each equal to 1 plus the number of lands you control.

Kyren Legate

If an opponent controls a Plains and you control a Mountain, you may cast this spell without paying its mana cost.
Haste

Lavaball Trap

If an opponent had two or more lands enter the battlefield under their control this turn, you may pay {3}{R}{R} rather than pay this spell's mana cost.
Destroy two target lands. Lavaball Trap deals 4 damage to each creature.

Patrician's Scorn

If you've cast another white spell this turn, you may cast this spell without paying its mana cost.
Destroy all enchantments.

Needlebite Trap

If an opponent gained life this turn, you may pay {B} rather than pay this spell's mana cost.
Target player loses 5 life and you gain 5 life.

Land Grant

If you have no land cards in hand, you may reveal your hand rather than pay this spell's mana cost.
Search your library for a Forest card, reveal that card, put it into your hand, then shuffle.

Vine Dryad

You may exile a green card from your hand rather than pay this spell's mana cost.
Flash
Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)

Fieldmist Borderpost

You may pay {1} and return a basic land you control to its owner's hand rather than pay this spell's mana cost.
Fieldmist Borderpost enters tapped.
{T}: Add {W} or {U}.

Cave-In

You may exile a red card from your hand rather than pay this spell's mana cost.
Cave-In deals 2 damage to each creature and each player.

Abolish

You may discard a Plains card rather than pay this spell's mana cost.
Destroy target artifact or enchantment.

Force of Despair

If it's not your turn, you may exile a black card from your hand rather than pay this spell's mana cost.
Destroy all creatures that entered this turn.

Misdirection

You may exile a blue card from your hand rather than pay this spell's mana cost.
Change the target of target spell with a single target.

Lashknife

If you control a Plains, you may tap an untapped creature you control rather than pay this spell's mana cost.
Enchant creature
Enchanted creature has first strike.

Commandeer

You may exile two blue cards from your hand rather than pay this spell's mana cost.
Gain control of target noncreature spell. You may choose new targets for it. (If that spell is an artifact, enchantment, or planeswalker, the permanent enters under your control.)

Crash

You may sacrifice a Mountain rather than pay this spell's mana cost.
Destroy target artifact.

Foil

You may discard an Island card and another card rather than pay this spell's mana cost.
Counter target spell.

Force of Virtue

If it's not your turn, you may exile a white card from your hand rather than pay this spell's mana cost.
Flash
Creatures you control get +1/+1.

Rouse

If you control a Swamp, you may pay 2 life rather than pay this spell's mana cost.
Target creature gets +2/+0 until end of turn.

Flameshot

You may discard a Mountain card rather than pay this spell's mana cost.
Flameshot deals 3 damage divided as you choose among one, two, or three target creatures.

Ramosian Rally

If you control a Plains, you may tap an untapped creature you control rather than pay this spell's mana cost.
Creatures you control get +1/+1 until end of turn.

Saprazzan Legate

If an opponent controls a Mountain and you control an Island, you may cast this spell without paying its mana cost.
Flying

Sivvi's Ruse

If an opponent controls a Mountain and you control a Plains, you may cast this spell without paying its mana cost.
Prevent all damage that would be dealt this turn to creatures you control.

Ensnare

You may return two Islands you control to their owner's hand rather than pay this spell's mana cost.
Tap all creatures.

Permafrost Trap

If an opponent had a green creature enter the battlefield under their control this turn, you may pay {U} rather than pay this spell's mana cost.
Tap up to two target creatures. Those creatures don't untap during their controller's next untap step.

Bringer of the Blue Dawn

You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost.
Trample
At the beginning of your upkeep, you may draw two cards.

Obscuring Haze

If you control a commander, you may cast this spell without paying its mana cost.
Prevent all damage that would be dealt this turn by creatures your opponents control.

Whiplash Trap

If an opponent had two or more creatures enter the battlefield under their control this turn, you may pay {U} rather than pay this spell's mana cost.
Return two target creatures to their owners' hands.

Golos, Tireless Pilgrim

When Golos, Tireless Pilgrim enters, you may search your library for a land card, put that card onto the battlefield tapped, then shuffle.
{2}{W}{U}{B}{R}{G}: Exile the top three cards of your library. You may play them this turn without paying their mana costs.

Dark Triumph

If you control a Swamp, you may sacrifice a creature rather than pay this spell's mana cost.
Creatures you control get +2/+0 until end of turn.

Firewild Borderpost

You may pay {1} and return a basic land you control to its owner's hand rather than pay this spell's mana cost.
Firewild Borderpost enters tapped.
{T}: Add {R} or {G}.

Snapback

You may exile a blue card from your hand rather than pay this spell's mana cost.
Return target creature to its owner's hand.

Inferno Trap

If you've been dealt damage by two or more creatures this turn, you may pay {R} rather than pay this spell's mana cost.
Inferno Trap deals 4 damage to target creature.

Runeflare Trap

If an opponent drew three or more cards this turn, you may pay {R} rather than pay this spell's mana cost.
Runeflare Trap deals damage to target player equal to the number of cards in that player's hand.

Plea for Guidance

Search your library for up to two enchantment cards, reveal them, put them into your hand, then shuffle.

Salvage Titan

You may sacrifice three artifacts rather than pay this spell's mana cost.
Exile three artifact cards from your graveyard: Return Salvage Titan from your graveyard to your hand.

Delraich

You may sacrifice three black creatures rather than pay this spell's mana cost.
Trample

Disrupting Shoal

You may exile a blue card with mana value X from your hand rather than pay this spell's mana cost.
Counter target spell if its mana value is X.

Admiral's Order

Raid — If you attacked this turn, you may pay {U} rather than pay this spell's mana cost.
Counter target spell.

Thunderclap

You may sacrifice a Mountain rather than pay this spell's mana cost.
Thunderclap deals 3 damage to target creature.

Bringer of the Black Dawn

You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost.
Trample
At the beginning of your upkeep, you may pay 2 life. If you do, search your library for a card, then shuffle and put that card on top.

Outbreak

You may discard a Swamp card rather than pay this spell's mana cost.
Choose a creature type. All creatures of that type get -1/-1 until end of turn.

Invigorate

If you control a Forest, rather than pay this spell's mana cost, you may have an opponent gain 3 life.
Target creature gets +4/+4 until end of turn.

Mindbreak Trap

If an opponent cast three or more spells this turn, you may pay {0} rather than pay this spell's mana cost.
Exile any number of target spells.

Bounty of the Hunt

You may exile a green card from your hand rather than pay this spell's mana cost.
Distribute three +1/+1 counters among one, two, or three target creatures. For each +1/+1 counter you put on a creature this way, remove a +1/+1 counter from that creature at the beginning of the next cleanup step.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Cho-Arrim Legate

If an opponent controls a Swamp and you control a Plains, you may cast this spell without paying its mana cost.
Protection from black

Downhill Charge

You may sacrifice a Mountain rather than pay this spell's mana cost.
Target creature gets +X/+0 until end of turn, where X is the number of Mountains you control.

Contagion

You may pay 1 life and exile a black card from your hand rather than pay this spell's mana cost.
Distribute two -2/-1 counters among one or two target creatures.

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Scars of the Veteran

You may exile a white card from your hand rather than pay this spell's mana cost.
Prevent the next 7 damage that would be dealt to any target this turn. If it's a creature, put a +0/+1 counter on it for each 1 damage prevented this way at the beginning of the next end step.

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Shining Shoal

You may exile a white card with mana value X from your hand rather than pay this spell's mana cost.
The next X damage that a source of your choice would deal to you and/or creatures you control this turn is dealt to any target instead.

Orim's Cure

If you control a Plains, you may tap an untapped creature you control rather than pay this spell's mana cost.
Prevent the next 4 damage that would be dealt to any target this turn.

Island

Massacre

If an opponent controls a Plains and you control a Swamp, you may cast this spell without paying its mana cost.
All creatures get -2/-2 until end of turn.

Snuff Out

If you control a Swamp, you may pay 4 life rather than pay this spell's mana cost.
Destroy target nonblack creature. It can't be regenerated.

Swamp

Cobra Trap

If a noncreature permanent under your control was destroyed this turn by a spell or ability an opponent controlled, you may pay {G} rather than pay this spell's mana cost.
Create four 1/1 green Snake creature tokens.

Unmask

You may exile a black card from your hand rather than pay this spell's mana cost.
Target player reveals their hand. You choose a nonland card from it. That player discards that card.

Coveted Prize

This spell costs {1} less to cast for each creature in your party. (Your party consists of up to one each of Cleric, Rogue, Warrior, and Wizard.)
Search your library for a card, put it into your hand, then shuffle. If you have a full party, you may cast a spell with mana value 4 or less from your hand without paying its mana cost.

Tidal Bore

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
You may tap or untap target creature.

Force of Rage

If it's not your turn, you may exile a red card from your hand rather than pay this spell's mana cost.
Create two 3/1 red Elemental creature tokens with trample and haste. Sacrifice those tokens at the beginning of your next upkeep.

Bringer of the White Dawn

You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost.
Trample
At the beginning of your upkeep, you may return target artifact card from your graveyard to the battlefield.

Ravenous Trap

If an opponent had three or more cards put into their graveyard from anywhere this turn, you may pay {0} rather than pay this spell's mana cost.
Exile target player's graveyard.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

Bringer of the Red Dawn

You may pay {W}{U}{B}{R}{G} rather than pay this spell's mana cost.
Trample
At the beginning of your upkeep, you may untap target creature and gain control of it until end of turn. That creature gains haste until end of turn.

Pitfall Trap

If exactly one creature is attacking, you may pay {W} rather than pay this spell's mana cost.
Destroy target attacking creature without flying.

Song of Creation

You may play an additional land on each of your turns.
Whenever you cast a spell, draw two cards.
At the beginning of your end step, discard your hand.

Mogg Alarm

You may sacrifice two Mountains rather than pay this spell's mana cost.
Create two 1/1 red Goblin creature tokens.

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

Empty the Warrens

Create two 1/1 red Goblin creature tokens.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Snag

You may discard a Forest card rather than pay this spell's mana cost.
Prevent all combat damage that would be dealt by unblocked creatures this turn.

Lethargy Trap

If three or more creatures are attacking, you may pay {U} rather than pay this spell's mana cost.
Attacking creatures get -3/-0 until end of turn.