Shifting Borders

Exchange control of two target lands.
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.)

Dreamcatcher

Whenever you cast a Spirit or Arcane spell, you may sacrifice Dreamcatcher. If you do, draw a card.

Baku Altar

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on Baku Altar.
{2}, {T}, Remove a ki counter from Baku Altar: Create a 1/1 colorless Spirit creature token.

Cut the Earthly Bond

Return target enchanted permanent to its owner's hand.

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.

Quillmane Baku

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on Quillmane Baku.
{1}, {T}, Remove X ki counters from Quillmane Baku: Return target creature with mana value X or less to its owner's hand.

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.)

Heed the Mists

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

Ideas Unbound

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

Ribbons of the Reikai

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.

Eye of Nowhere

Return target permanent to its owner's hand.

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.

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.)

Jade Idol

Whenever you cast a Spirit or Arcane spell, Jade Idol becomes a 4/4 Spirit artifact creature until end of turn.

Cloudhoof Kirin

Flying
Whenever you cast a Spirit or Arcane spell, you may have target player mill X cards, where X is that spell's mana value.

Part the Veil

Return all creatures you control to their owner's hand.

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.

Dampen Thought

Target player mills four cards.
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.)

Teller of Tales

Flying
Whenever you cast a Spirit or Arcane spell, you may tap or untap target creature.

Sire of the Storm

Flying
Whenever you cast a Spirit or Arcane spell, you may draw a card.

Arcane Adaptation

As Arcane Adaptation enters, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Reach Through Mists

Eerie Procession

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

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.)

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.)

Jaraku the Interloper

Remove a ki counter from Jaraku the Interloper: Counter target spell unless its controller pays {2}.

Callow Jushi

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on Callow Jushi.
At the beginning of the end step, if there are two or more ki counters on Callow Jushi, you may flip it.

Callow Jushi // Jaraku the Interloper

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.

Guardian of Solitude

Whenever you cast a Spirit or Arcane spell, target creature gains flying 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.

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.)

Long-Forgotten Gohei

Arcane spells you cast cost {1} less to cast.
Spirit creatures you control get +1/+1.

Stream of Consciousness

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

Kiri-Onna

When Kiri-Onna enters, return target creature to its owner's hand.
Whenever you cast a Spirit or Arcane spell, you may return Kiri-Onna to its owner's hand.

Toils of Night and Day

You may tap or untap target permanent, then you may tap or untap another target permanent.