Tidespout Tyrant

Flying
Whenever you cast a spell, return target permanent to its owner's hand.

Jace's Sanctum

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, scry 1.

Sphinx's Tutelage

Whenever you draw a card, target opponent mills two cards. If two nonland cards that share a color were milled this way, repeat this process.
{5}{U}: Draw a card, then discard a card.

The Great Synthesis

(As this Saga enters and after your draw step, add a lore counter.)
I — Draw cards equal to the number of cards in your hand. You have no maximum hand size for as long as you control The Great Synthesis.
II — Return all non-Phyrexian creatures to their owners' hands.
III — You may cast any number of spells from your hand without paying their mana costs. Exile The Great Synthesis, then return it to the battlefield (front face up).

Jin-Gitaxias

Ward {2}
Whenever you cast a noncreature spell with mana value 3 or greater, draw a card.
{3}{U}: Exile Jin-Gitaxias, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery and only if you have seven or more cards in hand.

Jin-Gitaxias // The Great Synthesis

Turbulent Dreams

As an additional cost to cast this spell, discard X cards.
Return X target nonland permanents to their owners' hands.

Flux Channeler

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Tezzeret's Gambit

({U/P} can be paid with either {U} or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Reject Imperfection

Counter target spell. If that spell's mana value was 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Psychic Corrosion

Whenever you draw a card, each opponent mills two cards.

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Leadership Vacuum

Target player returns each commander they control from the battlefield to the command zone.
Draw a card.

Fuel for the Cause

Counter target spell, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Relic of Legends

{T}: Add one mana of any color.
Tap an untapped legendary creature you control: Add one mana of any color.

Cloud Key

As Cloud Key enters, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Shipwreck Dowser

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When this creature enters, return target instant or sorcery card from your graveyard to your hand.

Mnemonic Nexus

Each player shuffles their graveyard into their library.

Transplant Theorist

Whenever Transplant Theorist or another artifact you control enters, you may draw a card. If you do, discard a card.
{2}: Put target card from your graveyard on the bottom of your library.

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

The Mightstone and Weakstone

When The Mightstone and Weakstone enters, choose one —
• Draw two cards.
• Target creature gets -5/-5 until end of turn.
{T}: Add {C}{C}. This mana can't be spent to cast nonartifact spells.
(Melds with Urza, Lord Protector.)

Thought Collapse

Counter target spell. Its controller mills three cards.

Vivisurgeon's Insight

Draw three cards. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Theft of Dreams

Draw a card for each tapped creature target opponent controls.

Font of Magic

Instant and sorcery spells you cast cost {1} less to cast for each time you've cast a commander from the command zone this game.

You Find the Villains' Lair

Choose one —
• Foil Their Scheme — Counter target spell.
• Learn Their Secrets — Draw two cards, then discard two cards.

Honored Heirloom

{T}: Add one mana of any color.
{2}, {T}: Exile target card from a graveyard.

Didn't Say Please

Frantic Search

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

Psychic Spiral

Shuffle all cards from your graveyard into your library. Target player mills that many cards.

Spinning Wheel

{T}: Add one mana of any color.
{5}, {T}: Tap target creature.

Deepglow Skate

When Deepglow Skate enters, double the number of each kind of counter on any number of target permanents.

Retract

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

Psychosis Crawler

Psychosis Crawler's power and toughness are each equal to the number of cards in your hand.
Whenever you draw a card, each opponent loses 1 life.

Unwind

Counter target noncreature spell. Untap up to three lands.

Rebuild

Return all artifacts to their owners' hands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice Stonespeaker Crystal: Exile any number of target players' graveyards. Draw a card.

Sol Ring

Winged Words

This spell costs {1} less to cast if you control a creature with flying.
Draw two cards.

Coalition Relic

{T}: Add one mana of any color.
{T}: Put a charge counter on Coalition Relic.
At the beginning of your first main phase, remove all charge counters from Coalition Relic. Add one mana of any color for each charge counter removed this way.

Clear the Mind

Target player shuffles their graveyard into their library.
Draw a card.

Gilded Lotus

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Steady Progress

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Jin-Gitaxias, Progress Tyrant

Whenever you cast an artifact, instant, or sorcery spell, copy that spell. You may choose new targets for the copy. This ability triggers only once each turn. (A copy of a permanent spell becomes a token.)
Whenever an opponent casts an artifact, instant, or sorcery spell, counter that spell. This ability triggers only once each turn.

Coveted Jewel

When Coveted Jewel enters, draw three cards.
{T}: Add three mana of any one color.
Whenever one or more creatures an opponent controls attack you and aren't blocked, that player draws three cards and gains control of Coveted Jewel. Untap it.

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Thran Dynamo

Counsel of the Soratami

Skyclave Relic

Kicker {3}
Indestructible
When Skyclave Relic enters, if it was kicked, create two tapped tokens that are copies of Skyclave Relic.
{T}: Add one mana of any color.

Divination

Mana Geode

When Mana Geode enters, scry 1.
{T}: Add one mana of any color.

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Island

Arcane Signet

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

Archaeomancer

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

Hurkyl's Recall

Return all artifacts target player owns to their hand.

Prologue to Phyresis

Each opponent gets a poison counter.
Draw a card.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Viral Drake

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Reliquary Tower

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

Keep Watch

Archmage's Charm

Choose one —
• Counter target spell.
• Target player draws two cards.
• Gain control of target nonland permanent with mana value 1 or less.

Trawler Drake

Flying
Trawler Drake enters with an oil counter on it.
Trawler Drake gets +1/+1 for each oil counter on it.
Whenever you cast a noncreature spell, put an oil counter on Trawler Drake.

Ominous Seas

Whenever you draw a card, put a foreshadow counter on Ominous Seas.
Remove eight foreshadow counters from Ominous Seas: Create an 8/8 blue Kraken creature token.
Cycling {2} ({2}, Discard this card: Draw a card.)

Secrets of the Golden City

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Draw two cards. If you have the city's blessing, draw three cards instead.

Visions of Duplicity

Exchange control of two target creatures you don't control.
Flashback {8}{U}{U}. This spell costs {X} less to cast this way, where X is the greatest mana value of a commander you own on the battlefield or in the command zone. (You may cast this card from your graveyard for its flashback cost. Then exile it.)