Iridian Maelstrom

Destroy each creature that isn't all colors.

Mountain

Case of the Shattered Pact

When this Case enters the battlefield, 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.

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.

Swamp

Path of Ancestry

Path of Ancestry enters the battlefield tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Sol Ring

Esper Charm

Choose one —
• Destroy target enchantment.
• Draw two cards.
• Target player discards two cards.

Naya Charm

Choose one —
• Naya Charm deals 3 damage to target creature.
• Return target card from a graveyard to its owner's hand.
• Tap all creatures target player controls.

Seaside Citadel

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

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.

Opulent Palace

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

Mystic Monastery

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

Golgari Charm

Choose one —
• All creatures get -1/-1 until end of turn.
• Destroy target enchantment.
• Regenerate each creature you control.

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.

Corpsejack Menace

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on it instead.

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.

Arcane Sanctum

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

Arcane Signet

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

Exotic Orchard

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

Fellwar Stone

Crosis's Charm

Choose one —
• Return target permanent to its owner's hand.
• Destroy target nonblack creature. It can't be regenerated.
• Destroy target artifact.

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.

Savage Lands

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

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Widespread Thieving

Hideaway 5 (When this enchantment enters the battlefield, look at the top five cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Whenever you cast a multicolored spell, create a Treasure token. Then you may pay {W}{U}{B}{R}{G}. If you do, you may play the exiled card without paying its mana cost.

Nethroi, Apex of Death

Mutate {4}{G/W}{B}{B} (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.)
Deathtouch, lifelink
Whenever this creature mutates, return any number of target creature cards with total power 10 or less from your graveyard to the battlefield.

Plains

Frontier Bivouac

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

Sandsteppe Citadel

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

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.

Obsidian Obelisk

Obsidian Obelisk enters the battlefield tapped.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a multicolored spell.

Forest

Rakdos Charm

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

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Sunken Hollow

({T}: Add {U} or {B}.)
Sunken Hollow enters the battlefield tapped unless you control two or more basic lands.

Farseek

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

Duneblast

Choose up to one creature. Destroy the rest.

Merciless Eviction

Choose one —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all planeswalkers.

Growth Spiral

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

General Ferrous Rokiric

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

Door to Nothingness

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

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.

Obscura Charm

Choose one —
• Return target multicolored permanent card with mana value 3 or less from your graveyard to the battlefield tapped.
• Counter target instant or sorcery spell.
• Destroy target creature or planeswalker with mana value 3 or less.

Command Tower

Omnath, Locus of All

If you would lose unspent mana, that mana becomes black instead.
At the beginning of your precombat 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.

Tome of the Guildpact

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

Whirlwind of Thought

Whenever you cast a noncreature spell, draw a card.

Primeval Spawn

If Primeval Spawn would enter the battlefield 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.

Canopy Vista

({T}: Add {G} or {W}.)
Canopy Vista enters the battlefield tapped unless you control two or more basic lands.

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.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

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}.

Jund Charm

Choose one —
• Exile target player's graveyard.
• Jund Charm deals 2 damage to each creature.
• Put two +1/+1 counters on target creature.

Jungle Shrine

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

Counterspell

Abzan Charm

Choose one —
• Exile target creature with power 3 or greater.
• You draw two cards and you lose 2 life.
• Distribute two +1/+1 counters among one or two target creatures.

Nomad Outpost

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

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

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.)

Annie Joins Up

When Annie Joins Up enters the battlefield, it deals 5 damage to target creature or planeswalker an opponent controls.
If a triggered ability of a legendary creature you control triggers, that ability triggers an additional time.

Jodah, Archmage Eternal

Flying
You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells that you cast.

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.

Cascading Cataracts

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

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.

Commander's Sphere

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

Crumbling Necropolis

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

Sultai Charm

Choose one —
• Destroy target monocolored creature.
• Destroy target artifact or enchantment.
• Draw two cards, then discard a card.

Chromatic Lantern

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

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 of your library in a random order.)

Maelstrom Wanderer

Creatures you control have haste.
Cascade, cascade (When you cast this 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 of your library in a random order. Then do it again.)

Lilah, Undefeated Slickshot

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast a multicolored instant or sorcery spell from your hand, exile that spell instead of putting it into your graveyard as it resolves. If you do, it becomes plotted. (You may cast it as a sorcery on a later turn without paying its mana cost.)

Bant Charm

Choose one —
• Destroy target artifact.
• Put target creature on the bottom of its owner's library.
• Counter target instant spell.

Brokers Charm

Choose one —
• Target creature you control gets +1/+0 until end of turn. It deals damage equal to its power to target creature or planeswalker an opponent controls.
• Destroy target enchantment.
• Draw two cards.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Island

Void Rend

This spell can't be countered.
Destroy target nonland permanent.

Reliquary Tower

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

Spelunking

When Spelunking enters the battlefield, draw a card, then you may put a land card from your hand onto the battlefield. If you put a Cave onto the battlefield this way, you gain 4 life.
Lands you control enter the battlefield untapped.