Have

Aragorn, the Uniter

Whenever you cast a white spell, create a 1/1 white Human Soldier creature token.
Whenever you cast a blue spell, scry 2.
Whenever you cast a red spell, Aragorn, the Uniter deals 3 damage to target opponent.
Whenever you cast a green spell, target creature gets +4/+4 until end of turn.

Conflux

Search your library for a white card, a blue card, a black card, a red card, and a green card. Reveal those cards, put them into your hand, then shuffle.

Boros Guildgate

Boros Guildgate enters tapped.
{T}: Add {R} or {W}.

Izzet Guildgate

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

Cromat

{W}{B}: Destroy target creature blocking or blocked by Cromat.
{U}{R}: Cromat gains flying until end of turn.
{B}{G}: Regenerate Cromat.
{R}{W}: Cromat gets +1/+1 until end of turn.
{G}{U}: Put Cromat on top of its owner's library.

Gond Gate

Gates you control enter untapped.
{T}: Add {C}.
{T}: Add one mana of any color that a Gate you control could produce.

Baleful Strix

Flying, deathtouch
When Baleful Strix enters, draw a card.

Sphinx of the Guildpact

Sphinx of the Guildpact is all colors.
Flying
Hexproof from monocolored (This creature can't be the target of monocolored spells or abilities your opponents control.)

Crumbling Necropolis

Crumbling Necropolis enters tapped.
{T}: Add {U}, {B}, or {R}.

Tiamat

Flying
When Tiamat enters, if you cast it, search your library for up to five Dragon cards not named Tiamat that each have different names, reveal them, put them into your hand, then shuffle.

Mystic Monastery

Mystic Monastery enters tapped.
{T}: Add {U}, {R}, or {W}.

Basilisk Gate

{T}: Add {C}.
{2}, {T}: Target creature gets +X/+X until end of turn, where X is the number of Gates you control. Activate only as a sorcery.

Chromanticore

Bestow {2}{W}{U}{B}{R}{G} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying, first strike, vigilance, trample, lifelink
Enchanted creature gets +4/+4 and has flying, first strike, vigilance, trample, and lifelink.

Nomad Outpost

Nomad Outpost enters tapped.
{T}: Add {R}, {W}, or {B}.

Exotic Orchard

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

Swamp

Maelstrom Nexus

The first spell you cast each turn has cascade. (When you cast your first spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

Awaken the Maelstrom

Awaken the Maelstrom is all colors.
Target player draws two cards. You may put an artifact card from your hand onto the battlefield. Create a token that's a copy of a permanent you control. Distribute three +1/+1 counters among one, two, or three creatures you control. Destroy target permanent an opponent controls.

Invasion of Alara

When Invasion of Alara enters, exile cards from the top of your library until you exile two nonland cards with mana value 4 or less. You may cast one of those two cards without paying its mana cost. Put one of them into your hand. Then put the other cards exiled this way on the bottom of your library in a random order.

Invasion of Alara // Awaken the Maelstrom

Omnath, Locus of All

If you would lose unspent mana, that mana becomes black instead.
At the beginning of your first main phase, look at the top card of your library. You may reveal that card if it has three or more colored mana symbols in its mana cost. If you do, add three mana in any combination of its colors and put it into your hand. If you don't reveal it, put it into your hand.

Fallaji Wayfarer

Fallaji Wayfarer is all colors. This ability doesn't affect its color identity. (It can be in any deck whose commander's color identity includes green.)
Multicolored spells you cast have convoke. (Your creatures can help cast those spells. Each creature you tap while casting a multicolored spell pays for {1} or one mana of a color that creature is.)

Lotho, Corrupt Shirriff

Whenever a player casts their second spell each turn, you lose 1 life and create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Faeburrow Elder

Vigilance
Faeburrow Elder gets +1/+1 for each color among permanents you control.
{T}: For each color among permanents you control, add one mana of that color.

Command Tower

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

Sandsteppe Citadel

Sandsteppe Citadel enters tapped.
{T}: Add {W}, {B}, or {G}.

Anguished Unmaking

Exile target nonland permanent. You lose 3 life.

Jenson Carthalion, Druid Exile

Whenever you cast a multicolored spell, scry 1. If that spell was all colors, create a 4/4 white Angel creature token with flying and vigilance.
{5}, {T}: Add {W}{U}{B}{R}{G}.

Cascading Cataracts

Indestructible
{T}: Add {C}.
{5}, {T}: Add five mana in any combination of colors.

Izzet Charm

Choose one —
• Counter target noncreature spell unless its controller pays {2}.
• Izzet Charm deals 2 damage to target creature.
• Draw two cards, then discard two cards.

Terminate

Destroy target creature. It can't be regenerated.

O-Kagachi Made Manifest

O-Kagachi Made Manifest is all colors.
Flying, trample
Whenever O-Kagachi Made Manifest attacks, defending player chooses a nonland card in your graveyard. Return that card to your hand. O-Kagachi Made Manifest gets +X/+0 until end of turn, where X is the mana value of that card.

The Kami War

(As this Saga enters and after your draw step, add a lore counter.)
I — Exile target nonland permanent an opponent controls.
II — Return up to one other target nonland permanent to its owner's hand. Then each opponent discards a card.
III — Exile this Saga, then return it to the battlefield transformed under your control.

The Kami War // O-Kagachi Made Manifest

Urban Evolution

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

Azorius Guildgate

Azorius Guildgate enters tapped.
{T}: Add {W} or {U}.

Forest

Two-Headed Hellkite

Flying, menace, haste
Whenever Two-Headed Hellkite attacks, draw two cards.

Crystal Quarry

{T}: Add {C}.
{5}, {T}: Add {W}{U}{B}{R}{G}.

General Ferrous Rokiric

Hexproof from monocolored
Whenever you cast a multicolored spell, create a 4/4 red and white Golem artifact creature token.

Vanishing Verse

Iridian Maelstrom

Destroy each creature that isn't all colors.

Simic Guildgate

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

Maelstrom Archangel

Flying
Whenever Maelstrom Archangel deals combat damage to a player, you may cast a spell from your hand without paying its mana cost.

Golgari Guildgate

Golgari Guildgate enters tapped.
{T}: Add {B} or {G}.

Gruul Guildgate

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

Bring to Light

Converge — Search your library for a creature, instant, or sorcery card with mana value less than or equal to the number of colors of mana spent to cast this spell, exile that card, then shuffle. You may cast that card without paying its mana cost.

Child of Alara

Trample
When Child of Alara dies, destroy all nonland permanents. They can't be regenerated.

Transguild Courier

Ramos, Dragon Engine

Flying
Whenever you cast a spell, put a +1/+1 counter on Ramos, Dragon Engine for each of that spell's colors.
Remove five +1/+1 counters from Ramos: Add {W}{W}{U}{U}{B}{B}{R}{R}{G}{G}. Activate only once each turn.

Door to Nothingness

Door to Nothingness enters tapped.
{W}{W}{U}{U}{B}{B}{R}{R}{G}{G}, {T}, Sacrifice Door to Nothingness: Target player loses the game.

Happily Ever After

When Happily Ever After enters, each player gains 5 life and draws a card.
At the beginning of your upkeep, if there are five colors among permanents you control, there are six or more card types among permanents you control and/or cards in your graveyard, and your life total is greater than or equal to your starting life total, you win the game.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Open the Gates

Search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Plains

O-Kagachi, Vengeful Kami

Flying, trample
Whenever O-Kagachi, Vengeful Kami deals combat damage to a player, if that player attacked you during their last turn, exile target nonland permanent that player controls.

Mountain

Gatecreeper Vine

Defender
When Gatecreeper Vine enters, you may search your library for a basic land card or a Gate card, reveal it, put it into your hand, then shuffle.

Jegantha, the Wellspring

Companion — No card in your starting deck has more than one of the same mana symbol in its mana cost. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
{T}: Add {W}{U}{B}{R}{G}. This mana can't be spent to pay generic mana costs.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Hero of Precinct One

Whenever you cast a multicolored spell, create a 1/1 white Human creature token.

Rakdos Charm

Choose one —
• Exile target player's graveyard.
• Destroy target artifact.
• Each creature deals 1 damage to its controller.

Rakdos Guildgate

Rakdos Guildgate enters tapped.
{T}: Add {B} or {R}.

Tome of the Guildpact

Whenever you cast a multicolored spell, draw a card.
{T}: Add one mana of any color.

Unite the Coalition

Choose five. You may choose the same mode more than once.
• Target permanent phases out.
• Target player draws a card.
• Exile target player's graveyard.
• Unite the Coalition deals 2 damage to any target.
• Destroy target artifact or enchantment.

Eureka Moment

Draw two cards. You may put a land card from your hand onto the battlefield.

Dimir Guildgate

Dimir Guildgate enters tapped.
{T}: Add {U} or {B}.

Putrefy

Destroy target artifact or creature. It can't be regenerated.

Frontier Bivouac

Frontier Bivouac enters tapped.
{T}: Add {G}, {U}, or {R}.

Savage Lands

Savage Lands enters tapped.
{T}: Add {B}, {R}, or {G}.

Knight of New Alara

Each other multicolored creature you control gets +1/+1 for each of its colors.

Primeval Spawn

If Primeval Spawn would enter and it wasn't cast or no mana was spent to cast it, exile it instead.
Vigilance, trample, lifelink
When Primeval Spawn leaves the battlefield, exile the top ten cards of your library. You may cast any number of spells with total mana value 10 or less from among them without paying their mana costs.

Orzhov Guildgate

Orzhov Guildgate enters tapped.
{T}: Add {W} or {B}.

Notion Rain

Surveil 2, then draw two cards. Notion Rain deals 2 damage to you. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Urza's Filter

Multicolored spells cost {2} less to cast.

Rienne, Angel of Rebirth

Flying
Other multicolored creatures you control get +1/+0.
Whenever another multicolored creature you control dies, return it to its owner's hand at the beginning of the next end step.

Maze's End

Maze's End enters tapped.
{T}: Add {C}.
{3}, {T}, Return Maze's End to its owner's hand: Search your library for a Gate card, put it onto the battlefield, then shuffle. If you control ten or more Gates with different names, you win the game.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Circuitous Route

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.

Garth One-Eye

{T}: Choose a card name that hasn't been chosen from among Disenchant, Braingeyser, Terror, Shivan Dragon, Regrowth, and Black Lotus. Create a copy of the card with the chosen name. You may cast the copy. (You still pay its costs.)

Opulent Palace

Opulent Palace enters tapped.
{T}: Add {B}, {G}, or {U}.

Leyline of the Guildpact

If Leyline of the Guildpact is in your opening hand, you may begin the game with it on the battlefield.
Each nonland permanent you control is all colors.
Lands you control are every basic land type in addition to their other types.

Thrilling Discovery

You gain 2 life. Then you may discard two cards. If you do, draw three cards.

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.

Seaside Citadel

Seaside Citadel enters tapped.
{T}: Add {G}, {W}, or {U}.

Coiling Oracle

When Coiling Oracle enters, 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.

District Guide

When District Guide enters, you may search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Mana Cannons

Whenever you cast a multicolored spell, Mana Cannons deals X damage to any target, where X is the number of colors that spell is.

Jungle Shrine

Jungle Shrine enters tapped.
{T}: Add {R}, {G}, or {W}.

Spirit of Resistance

As long as you control a permanent of each color, prevent all damage that would be dealt to you.

Fusion Elemental

Scion of Draco

Domain — This spell costs {2} less to cast for each basic land type among lands you control.
Flying
Each creature you control has vigilance if it's white, hexproof if it's blue, lifelink if it's black, first strike if it's red, and trample if it's green.

Arcane Sanctum

Arcane Sanctum enters tapped.
{T}: Add {W}, {U}, or {B}.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Island

Niv-Mizzet Reborn

Flying
When Niv-Mizzet Reborn enters, reveal the top ten cards of your library. For each color pair, choose a card that's exactly those colors from among them. Put the chosen cards into your hand and the rest on the bottom of your library in a random order.

Selesnya Guildgate

Selesnya Guildgate enters tapped.
{T}: Add {G} or {W}.

Case of the Shattered Pact

When this Case enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
To solve — There are five colors among permanents you control. (If unsolved, solve at the beginning of your end step.)
Solved — At the beginning of combat on your turn, target creature you control gains flying, double strike, and vigilance until end of turn.

Niv-Mizzet, Guildpact

Flying, hexproof from multicolored
Whenever Niv-Mizzet, Guildpact deals combat damage to a player, it deals X damage to any target, target player draws X cards, and you gain X life, where X is the number of different color pairs among permanents you control that are exactly two colors.

Jared Carthalion

+1: Create a 3/3 Kavu creature token with trample that's all colors.
−3: Choose up to two target creatures. For each of them, put a number of +1/+1 counters on it equal to the number of colors it is.
−6: Return target multicolored card from your graveyard to your hand. If that card was all colors, draw a card and create two Treasure tokens.
Jared Carthalion can be your commander.