Original

Haldan, Avid Arcanist

Partner with Pako, Arcane Retriever (When this creature enters the battlefield, target player may put Pako into their hand from their library, then shuffle.)
You may play lands and cast noncreature spells from among cards you exiled that have fetch counters on them, and you may spend mana as though it were mana of any color to cast those spells.

Fertilid

Fertilid enters the battlefield with two +1/+1 counters on it.
{1}{G}, Remove a +1/+1 counter from Fertilid: Target player searches their library for a basic land card, puts it onto the battlefield tapped, then shuffles.

My Additions

Arcane Signet

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

Swiftwater Cliffs

Swiftwater Cliffs enters the battlefield tapped.
When Swiftwater Cliffs enters the battlefield, you gain 1 life.
{T}: Add {U} or {R}.

Feldon's Cane

{T}, Exile Feldon's Cane: Shuffle your graveyard into your library.

Think Tank

At the beginning of your upkeep, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Passionate Archaeologist

Commander creatures you own have "Whenever you cast a spell from exile, this creature deals damage equal to that spell's mana value to target opponent."

Savage Twister

Savage Twister deals X damage to each creature.

Gruul Turf

Gruul Turf enters the battlefield tapped.
When Gruul Turf enters the battlefield, return a land you control to its owner's hand.
{T}: Add {R}{G}.

Coiling Oracle

When Coiling Oracle enters the battlefield, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put that card into your hand.

Thornwood Falls

Thornwood Falls enters the battlefield tapped.
When Thornwood Falls enters the battlefield, you gain 1 life.
{T}: Add {G} or {U}.

Chemister's Insight

Draw two cards.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Retreat to Coralhelm

Landfall — Whenever a land enters the battlefield under your control, choose one —
• You may tap or untap target creature.
• Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Temur Charm

Choose one —
• Target creature you control gets +1/+1 until end of turn. It fights target creature you don't control.
• Counter target spell unless its controller pays {3}.
• Creatures with power 3 or less can't block this turn.

Darksteel Pendant

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{1}, {T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Psychic Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you scry 2.

Sol Ring

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.

Font of Fertility

{1}{G}, Sacrifice Font of Fertility: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Maraleaf Pixie

Primal Command

Choose two —
• Target player gains 7 life.
• Put target noncreature permanent on top of its owner's library.
• Target player shuffles their graveyard into their library.
• Search your library for a creature card, reveal it, put it into your hand, then shuffle.

Rupture Spire

Rupture Spire enters the battlefield tapped.
When Rupture Spire enters the battlefield, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Once and Future

Return target card from your graveyard to your hand. Put up to one other target card from your graveyard on top of your library. Exile Once and Future.
Adamant — If at least three green mana was spent to cast this spell, instead return those cards to your hand and exile Once and Future.

Reclaim

Put target card from your graveyard on top of your library.

Expel from Orazca

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Return target nonland permanent to its owner's hand. If you have the city's blessing, you may put that permanent on top of its owner's library instead.

Firebrand Archer

Whenever you cast a noncreature spell, Firebrand Archer deals 1 damage to each opponent.

Shiny Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Ghoulcaller's Bell

Aether Tunnel

Enchant creature
Enchanted creature gets +1/+0 and can't be blocked.

Simic Guildgate

Simic Guildgate enters the battlefield tapped.
{T}: Add {G} or {U}.

Temur Battle Rage

Target creature gains double strike until end of turn.
Ferocious — That creature also gains trample until end of turn if you control a creature with power 4 or greater.

Acidic Slime

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
When Acidic Slime enters the battlefield, destroy target artifact, enchantment, or land.

Blinding Fog

Prevent all damage that would be dealt to creatures this turn. Creatures you control gain hexproof until end of turn. (They can't be the targets of spells or abilities your opponents control.)

Elixir of Immortality

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

Izzet Boilerworks

Izzet Boilerworks enters the battlefield tapped.
When Izzet Boilerworks enters the battlefield, return a land you control to its owner's hand.
{T}: Add {U}{R}.

Nissa's Renewal

Search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle. You gain 7 life.

Hinder

Counter target spell. If that spell is countered this way, put that card on the top or bottom of its owner's library instead of into that player's graveyard.

Urban Evolution

Draw three cards. You may play an additional land this turn.

Niblis of Frost

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast an instant or sorcery spell, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Key to the City

{T}, Discard a card: Up to one target creature can't be blocked this turn.
Whenever Key to the City becomes untapped, you may pay {2}. If you do, draw a card.

Perpetual Timepiece

{T}: Mill two cards.
{2}, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

Soulbright Flamekin

{2}: Target creature gains trample until end of turn. If this is the third time this ability has resolved this turn, you may add {R}{R}{R}{R}{R}{R}{R}{R}.

Forest

Precognition Field

You may look at the top card of your library any time.
You may cast instant and sorcery spells from the top of your library.
{3}: Exile the top card of your library.

Gruul Guildgate

Gruul Guildgate enters the battlefield tapped.
{T}: Add {R} or {G}.

Lantern of Insight

Players play with the top card of their libraries revealed.
{T}, Sacrifice Lantern of Insight: Target player shuffles.

Fertile Ground

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Codex Shredder

{T}: Target player mills a card. (They put the top card of their library into their graveyard.)
{5}, {T}, Sacrifice Codex Shredder: Return target card from your graveyard to your hand.

Saheeli, Sublime Artificer

Whenever you cast a noncreature spell, create a 1/1 colorless Servo artifact creature token.
−2: Target artifact you control becomes a copy of another target artifact or creature you control until end of turn, except it's an artifact in addition to its other types.

Totally Lost

Put target nonland permanent on top of its owner's library.

Bonder's Ornament

{T}: Add one mana of any color.
{4}, {T}: Each player who controls a permanent named Bonder's Ornament draws a card.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Woodland Stream

Woodland Stream enters the battlefield tapped.
{T}: Add {G} or {U}.

Mountain

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Parcelbeast

Mutate {G}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
{1}, {T}: Look at the top card of your library. If it's a land card, you may put it onto the battlefield. If you don't put the card onto the battlefield, put it into your hand.

Psychic Spiral

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

Explorer's Scope

Whenever equipped creature attacks, look at the top card of your library. If it's a land card, you may put it onto the battlefield tapped.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Lens of Clarity

You may look at the top card of your library and at face-down creatures you don't control any time.

Natural Connection

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Kazandu Refuge

Kazandu Refuge enters the battlefield tapped.
When Kazandu Refuge enters the battlefield, you gain 1 life.
{T}: Add {R} or {G}.

Dispel

You See a Guard Approach

Choose one —
• Distract the Guard — Tap target creature.
• Hide — Target creature you control gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Memory Lapse

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Izzet Guildgate

Izzet Guildgate enters the battlefield tapped.
{T}: Add {U} or {R}.

Weirding Wood

Enchant land
When Weirding Wood enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Enchanted land has "{T}: Add two mana of any one color."

Temporal Spring

Put target permanent on top of its owner's library.

Primal Empathy

At the beginning of your upkeep, draw a card if you control a creature with the greatest power among creatures on the battlefield. Otherwise, put a +1/+1 counter on a creature you control.

Island

Wolfwillow Haven

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.
{4}{G}, Sacrifice Wolfwillow Haven: Create a 2/2 green Wolf creature token. Activate only during your turn.

Rugged Highlands

Rugged Highlands enters the battlefield tapped.
When Rugged Highlands enters the battlefield, you gain 1 life.
{T}: Add {R} or {G}.

Burning Prophet

Whenever you cast a noncreature spell, Burning Prophet gets +1/+0 until end of turn, then scry 1.

Ketria Crystal

{T}: Add {G}, {U}, or {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Pako, Arcane Retriever

Partner with Haldan, Avid Arcanist
Haste
Whenever Pako, Arcane Retriever attacks, exile the top card of each player's library and put a fetch counter on each of them. Put a +1/+1 counter on Pako for each noncreature card exiled this way.

Vanishment

Put target nonland permanent on top of its owner's library.
Miracle {U} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Blossoming Defense

Target creature you control gets +2/+2 and gains hexproof until end of turn.

Blood Mist

At the beginning of combat on your turn, target creature you control gains double strike until end of turn.

Reap the Past

Return X cards at random from your graveyard to your hand. Exile Reap the Past.

Hunter's Insight

Choose target creature you control. Whenever that creature deals combat damage to a player or planeswalker this turn, draw that many cards.