Lifted by Clouds

Target creature gains flying until end of turn.
Splice onto Arcane {1}{U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Mystic Monastery

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

Simic Signet

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.

Inner Calm, Outer Strength

Target creature gets +X/+X until end of turn, where X is the number of cards in your hand.

Veil of Secrecy

Target creature gains shroud until end of turn and can't be blocked this turn. (A creature with shroud can't be the target of spells or abilities.)
Splice onto Arcane—Return a blue creature you control to its owner's hand. (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

First Volley

First Volley deals 1 damage to target creature and 1 damage to that creature's controller.

Izzet Signet

Boros Signet

Unnatural Speed

Target creature gains haste until end of turn.

Karplusan Forest

{T}: Add {C}.
{T}: Add {R} or {G}. This land deals 1 damage to you.

Into the Fray

Target creature attacks this turn if able.
Splice onto Arcane {R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Ideas Unbound

Draw three cards. Discard three cards at the beginning of the next end step.

Azorius Signet

Botanical Sanctum

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

Vital Surge

You gain 3 life.
Splice onto Arcane {1}{G} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Cleanfall

Razorverge Thicket

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

Eerie Procession

Search your library for an Arcane card, reveal that card, put it into your hand, then shuffle.

Solve the Equation

Search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. This land deals 1 damage to you.

Copperline Gorge

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

Plaza of Heroes

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell.
{T}: Add one mana of any color among legendary permanents you control.
{3}, {T}, Exile this land: Target legendary creature gains hexproof and indestructible until end of turn.

The Unspeakable

Flying, trample
Whenever The Unspeakable deals combat damage to a player, you may return target Arcane card from your graveyard to your hand.

Eye of Nowhere

Return target permanent to its owner's hand.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. This land deals 1 damage to you.

Forest

Kodama's Might

Target creature gets +2/+2 until end of turn.
Splice onto Arcane {G} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Strange Inversion

Switch target creature's power and toughness until end of turn.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Consuming Vortex

Return target creature to its owner's hand.
Splice onto Arcane {3}{U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Devouring Rage

As an additional cost to cast this spell, you may sacrifice any number of Spirits.
Target creature gets +3/+0 until end of turn. For each Spirit sacrificed this way, that creature gets an additional +3/+0 until end of turn.

Psychic Puppetry

You may tap or untap target permanent.
Splice onto Arcane {U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Petals of Insight

Look at the top three cards of your library. You may put those cards on the bottom of your library in any order. If you do, return Petals of Insight to its owner's hand. Otherwise, draw three cards.

Hundred-Talon Strike

Target creature gets +1/+0 and gains first strike until end of turn.
Splice onto Arcane—Tap an untapped white creature you control. (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Ethereal Haze

Prevent all damage that would be dealt by creatures this turn.

Stream of Consciousness

Target player shuffles up to four target cards from their graveyard into their library.

Forbidden Orchard

{T}: Add one mana of any color.
Whenever you tap this land for mana, target opponent creates a 1/1 colorless Spirit creature token.

Island

Sift Through Sands

Draw two cards, then discard a card.
If you've cast a spell named Peer Through Depths and a spell named Reach Through Mists this turn, you may search your library for a card named The Unspeakable, put it onto the battlefield, then shuffle.

Plains

Joyous Respite

You gain 1 life for each land you control.

Jungle Shrine

This land enters tapped.
{T}: Add {R}, {G}, or {W}.

Nourishing Shoal

You may exile a green card with mana value X from your hand rather than pay this spell's mana cost.
You gain X life.

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. This land deals 1 damage to you.

Spiritual Visit

Create a 1/1 colorless Spirit creature token.
Splice onto Arcane {W} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

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.

Overblaze

Each time target permanent would deal damage to a permanent or player this turn, it deals double that damage to that permanent or player instead.
Splice onto Arcane {2}{R}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Spiraling Embers

Spiraling Embers deals damage to any target equal to the number of cards in your hand.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Seachrome Coast

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

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.

Wear Away

Destroy target artifact or enchantment.
Splice onto Arcane {3}{G} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Inspiring Vantage

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

Reweave

Target permanent's controller sacrifices it. If the player does, they reveal cards from the top of their library until they reveal a permanent card that shares a card type with the sacrificed permanent, put that card onto the battlefield, then shuffle.
Splice onto Arcane {2}{U}{U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Expedite

Target creature gains haste until end of turn.
Draw a card.

Unchecked Growth

Target creature gets +4/+4 until end of turn. If it's a Spirit, it gains trample until end of turn.

Ire of Kaminari

Ire of Kaminari deals damage to any target equal to the number of Arcane cards in your graveyard.

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.

Crack the Earth

Each player sacrifices a permanent of their choice.

Command Tower

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

Blessed Breath

Target creature you control gains protection from the color of your choice until end of turn.
Splice onto Arcane {W} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Murmurs from Beyond

Reveal the top three cards of your library. An opponent chooses one of them. Put that card into your graveyard and the rest into your hand.

Selesnya Signet

Peer Through Depths

Look at the top five cards of your library. You may reveal an instant or sorcery card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Glacial Ray

Glacial Ray deals 2 damage to any target.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Otherworldly Journey

Exile target creature. At the beginning of the next end step, return that card to the battlefield under its owner's control with a +1/+1 counter on it.

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Quiet Purity

Mountain

Evermind

(Nonexistent mana costs can't be paid.)
Draw a card.
Splice onto Arcane {1}{U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Gruul Signet

Arcane Signet

Rending Vines

Destroy target artifact or enchantment if its mana value is less than or equal to the number of cards in your hand.
Draw a card.

Candles' Glow

Prevent the next 3 damage that would be dealt to any target this turn. You gain life equal to the damage prevented this way.
Splice onto Arcane {1}{W} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Seaside Citadel

This land enters tapped.
{T}: Add {G}, {W}, or {U}.

Sol Ring

Merchant Scroll

Search your library for a blue instant card, reveal that card, put it into your hand, then shuffle.

Unearthly Blizzard

Up to three target creatures can't block this turn.

Heed the Mists

Mill a card, then draw cards equal to the milled card's mana value.

Spirebluff Canal

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

Frontier Bivouac

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

Torrent of Stone

Torrent of Stone deals 4 damage to target creature.
Splice onto Arcane—Sacrifice two Mountains. (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Brushland

{T}: Add {C}.
{T}: Add {G} or {W}. This land deals 1 damage to you.

Ink-Treader Nephilim

Whenever a player casts an instant or sorcery spell, if that spell targets only this creature, copy the spell for each other creature that spell could target. Each copy targets a different one of those creatures.