Knowledge Exploitation

Prowl {3}{U} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Rogue.)
Search target opponent's library for an instant or sorcery card. You may cast that card without paying its mana cost. Then that player shuffles.

Caetus, Sea Tyrant of Segovia

Noncreature spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting a noncreature spell pays for {1} or one mana of that creature's color.)
At the beginning of your end step, untap up to four target creatures.

Invasion of Segovia

(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 Invasion of Segovia enters, create two 1/1 blue Kraken creature tokens with trample.

Invasion of Segovia // Caetus, Sea Tyrant of Segovia

Fellwar Stone

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

Treasure Cruise

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Draw three cards.

Brainstorm

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

Cloak and Dagger

Equipped creature gets +2/+0 and has shroud. (It can't be the target of spells or abilities.)
Whenever a Rogue creature enters, you may attach Cloak and Dagger to it.
Equip {3}

Clout of the Dominus

Enchant creature
As long as enchanted creature is blue, it gets +1/+1 and has shroud. (It can't be the target of spells or abilities.)
As long as enchanted creature is red, it gets +1/+1 and has haste.

Mountain

River Song

Meet in Reverse — You draw cards from the bottom of your library rather than the top.
Spoilers — Whenever an opponent scries, surveils, or searches their library, put a +1/+1 counter on River Song. Then River Song deals damage to that player equal to its power.

Shark Typhoon

Whenever you cast a noncreature spell, create an X/X blue Shark creature token with flying, where X is that spell's mana value.
Cycling {X}{1}{U} ({X}{1}{U}, Discard this card: Draw a card.)
When you cycle Shark Typhoon, create an X/X blue Shark creature token with flying.

Whirlwind Denial

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

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Big Score

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Izzet Signet

Solve the Equation

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

Tomb Trawler

{2}: Put target card from your graveyard on the bottom of your library.

Trenzalore Clocktower

{T}: Add {U}. Put a time counter on Trenzalore Clocktower.
{1}{U}, {T}, Remove twelve time counters from Trenzalore Clocktower and exile it: Shuffle your graveyard and hand into your library, then draw seven cards. Activate only if you control a Time Lord.

Conjurer's Bauble

{T}, Sacrifice Conjurer's Bauble: Put up to one target card from your graveyard on the bottom of your library. Draw a card.

Fury Storm

When you cast this spell, copy it for each time you've cast your commander from the command zone this game. You may choose new targets for the copies.
Copy target instant or sorcery spell. You may choose new targets for the copy.

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.

Fblthp, Lost on the Range

Ward {2}
You may look at the top card of your library any time.
The top card of your library has plot. The plot cost is equal to its mana cost.
You may plot nonland cards from the top of your library.

Forger's Foundry

{T}: Add {U}. When you spend this mana to cast an instant or sorcery spell with mana value 3 or less, you may exile that spell instead of putting it into its owner's graveyard as it resolves.
{3}{U}{U}, {T}: You may cast any number of spells from among cards exiled with Forger's Foundry without paying their mana costs. Activate only as a sorcery.

Radiant Performer

Flash
When Radiant Performer enters, if you cast it from your hand, choose target spell or ability that targets only a single permanent or player. Copy that spell or ability for each other permanent or player the spell or ability could target. Each copy targets a different one of those permanents and players.

Imprisoned in the Moon

Enchant creature, land, or planeswalker
Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.

Cleansing Wildfire

Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.
Draw a card.

Ardent Elementalist

When Ardent Elementalist enters, return target instant or sorcery card from your graveyard to your hand.

Temple of Cyclical Time

(Transforms from Ojer Pakpatiq, Deepest Epoch.)
{T}: Add {U}. Remove a time counter from Temple of Cyclical Time.
{2}{U}, {T}: Transform Temple of Cyclical Time. Activate only if it has no time counters on it and only as a sorcery.

Ojer Pakpatiq, Deepest Epoch

Flying
Whenever you cast an instant spell from your hand, it gains rebound. (Exile it as it resolves. At the beginning of your next upkeep, you may cast it from exile without paying its mana cost.)
When Ojer Pakpatiq dies, return it to the battlefield tapped and transformed under its owner's control with three time counters on it.

Ojer Pakpatiq, Deepest Epoch // Temple of Cyclical Time

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

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.)

Winged Boots

Equipped creature has flying and ward {4}. (Whenever equipped creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {4}.)
Equip {1}

Burning Earth

Whenever a player taps a nonbasic land for mana, Burning Earth deals 1 damage to that player.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Aetherize

Return all attacking creatures to their owner's hand.

Magus of the Moon

Living Lightning

When Living Lightning dies, return target instant or sorcery card from your graveyard to your hand.

Arcane Signet

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

Spellseeker

When Spellseeker enters, you may search your library for an instant or sorcery card with mana value 2 or less, reveal it, put it into your hand, then shuffle.

Krenko's Buzzcrusher

Flying, trample
When Krenko's Buzzcrusher enters, for each player, destroy up to one nonbasic land that player controls. For each land destroyed this way, its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Sol Ring

Reito Lantern

{3}: Put target card from a graveyard on the bottom of its owner's library.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Vandalblast

Destroy target artifact you don't control.
Overload {4}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Reverberate

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

Winter Moon

Players can't untap more than one nonbasic land during their untap steps.

Vexing Scuttler

Emerge {6}{U} (You may cast this spell by sacrificing a creature and paying the emerge cost reduced by that creature's mana value.)
When you cast this spell, you may return target instant or sorcery card from your graveyard to your hand.

Island

Radiate

Choose target instant or sorcery spell that targets only a single permanent or player. Copy that spell for each other permanent or player the spell could target. Each copy targets a different one of those permanents and players.

Wild Ricochet

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

Thran Dynamo

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Spires of Orazca

(Transforms from Thaumatic Compass.)
{T}: Add {C}.
{T}: Untap target attacking creature an opponent controls and remove it from combat.

Thaumatic Compass

{3}, {T}: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
At the beginning of your end step, if you control seven or more lands, transform Thaumatic Compass.

Thaumatic Compass // Spires of Orazca

Third Path Iconoclast

Whenever you cast a noncreature spell, create a 1/1 colorless Soldier artifact creature token.

Melek, Reforged Researcher

Melek, Reforged Researcher's power and toughness are each equal to twice the number of instant and sorcery cards in your graveyard.
The first instant or sorcery spell you cast each turn costs {3} less to cast.

Return the Favor

Spree (Choose one or more additional costs.)
+ {1} — Copy target instant spell, sorcery spell, activated ability, or triggered ability. You may choose new targets for the copy.
+ {1} — Change the target of target spell or ability with a single target.

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Refraction Elemental

Ward—Pay 2 life.
Whenever you cast a spell, Refraction Elemental deals 2 damage to each opponent.

Invasion of Karsus

(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 Invasion of Karsus enters, it deals 3 damage to each creature and each planeswalker.

Invasion of Karsus // Refraction Elemental

Solphim, Mayhem Dominus

If a source you control would deal noncombat damage to an opponent or a permanent an opponent controls, it deals double that damage to that player or permanent instead.
{1}{R/P}{R/P}, Discard two cards: Put an indestructible counter on Solphim, Mayhem Dominus. ({R/P} can be paid with either {R} or 2 life.)

Metallurgic Summonings

Whenever you cast an instant or sorcery spell, create an X/X colorless Construct artifact creature token, where X is that spell's mana value.
{3}{U}{U}, Exile Metallurgic Summonings: Return all instant and sorcery cards from your graveyard to your hand. Activate only if you control six or more artifacts.

Archaeomancer

When Archaeomancer enters, return target instant or sorcery card from your graveyard to your hand.

Thieves' Fortune

Prowl {U} (You may cast this for its prowl cost if you dealt combat damage to a player this turn with a Rogue.)
Look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Counterspell

Bolt Bend

This spell costs {3} less to cast if you control a creature with power 4 or greater.
Change the target of target spell or ability with a single target.

Expressive Iteration

Look at the top three cards of your library. Put one of them into your hand, put one of them on the bottom of your library, and exile one of them. You may play the exiled card this turn.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Demolition Field

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Destroy target nonbasic land an opponent controls. That land's controller may search their library for a basic land card, put it onto the battlefield, then shuffle. You may search your library for a basic land card, put it onto the battlefield, then shuffle.

Blood Moon

Price of Progress

Price of Progress deals damage to each player equal to twice the number of nonbasic lands that player controls.