Blessing of the Nephilim

Enchant creature
Enchanted creature gets +1/+1 for each of its colors.

Arvad the Cursed

Deathtouch, lifelink
Other legendary creatures you control get +2/+2.

Esper Stormblade

As long as you control another multicolored permanent, this creature gets +1/+1 and has flying.

Dawn's Reflection

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional two mana in any combination of colors.

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}.

Day of Destiny

Legendary creatures you control get +2/+2.

Earnest Fellowship

Each creature has protection from its colors.

Dragon Arch

{2}, {T}: You may put a multicolored creature card from your hand onto the battlefield.

Maze Sentinel

Vigilance
Multicolored creatures you control have vigilance.

Maze Rusher

Haste
Multicolored creatures you control have haste.

Mox Amber

{T}: Add one mana of any color among legendary creatures and planeswalkers you control.

Jodah, the Unifier

Legendary creatures you control get +X/+X, where X is the number of legendary creatures you control.
Whenever you cast a legendary spell from your hand, exile cards from the top of your library until you exile a legendary nonland card with lesser mana value. You may cast that card without paying its mana cost. Put the rest on the bottom of your library in a random order.

Hero of Precinct One

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

Chandra, Hope's Beacon

Whenever you cast an instant or sorcery spell, copy it. You may choose new targets for the copy. This ability triggers only once each turn.
+2: Add two mana in any combination of colors.
+1: Exile the top five cards of your library. Until the end of your next turn, you may cast an instant or sorcery spell from among those exiled cards.
−X: Chandra deals X damage to each of up to two targets.

Mana Cannons

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

Colonel Autumn

Lifelink
Exploit (When this creature enters, you may sacrifice a creature.)
Other legendary creatures you control have exploit.
Whenever a creature you control exploits a creature, put a +1/+1 counter on each creature you control.

Bant Sureblade

As long as you control another multicolored permanent, this creature gets +1/+1 and has first strike.

Rising of the Day

Creatures you control have haste.
Legendary creatures you control get +1/+0.

Naya Hushblade

As long as you control another multicolored permanent, this creature gets +1/+1 and has shroud. (It can't be the target of spells or abilities.)

Knight of New Alara

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

Bard Class

(Gain the next level as a sorcery to add its ability.)
Legendary creatures you control enter with an additional +1/+1 counter on them.
{R}{G}: Level 2
Legendary spells you cast cost {R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
{3}{R}{G}: Level 3
Whenever you cast a legendary spell, exile the top two cards of your library. You may play them this turn.

Glass of the Guildpact

Multicolored creatures you control get +1/+1.

Maze Glider

Flying
Multicolored creatures you control have flying.

The Seriema

When The Seriema enters, search your library for a legendary creature card, reveal it, put it into your hand, then shuffle.
Station (Tap another creature you control: Put charge counters equal to its power on this Spacecraft. Station only as a sorcery. It's an artifact creature at 7+.)
7+ | Flying
Other tapped legendary creatures you control have indestructible.

Midnight Pathlighter

Creatures you control can't be blocked except by legendary creatures.
Whenever one or more creatures you control deal combat damage to a player, venture into the dungeon. (Enter the first room or advance to the next room.)

Arcane Signet

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

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.

Cleopatra, Exiled Pharaoh

Allies — At the beginning of your end step, put a +1/+1 counter on each of up to two other target legendary creatures.
Betrayal — Whenever a legendary creature with counters on it dies, draw a card for each counter on it. You lose 2 life.

General Ferrous Rokiric

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

Infinite Guideline Station

When Infinite Guideline Station enters, create a tapped 2/2 colorless Robot artifact creature token for each multicolored permanent you control.
Station (Tap another creature you control: Put charge counters equal to its power on this Spacecraft. Station only as a sorcery. It's an artifact creature at 12+.)
12+ | Flying
Whenever Infinite Guideline Station attacks, draw a card for each multicolored permanent you control.

Jund Hackblade

As long as you control another multicolored permanent, this creature gets +1/+1 and has haste.

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.)

Éowyn, Fearless Knight

Haste
When Éowyn enters, exile target creature an opponent controls with greater power. Legendary creatures you control gain protection from each of that creature's colors until end of turn.

Elemental Resonance

Enchant permanent
At the beginning of your first main phase, add mana equal to enchanted permanent's mana cost. (Mana cost includes color. If a mana symbol has multiple colors, choose one.)

Flowering of the White Tree

Legendary creatures you control get +2/+1 and have ward {1}.
Nonlegendary creatures you control get +1/+1.

Grixis Grimblade

As long as you control another multicolored permanent, this creature gets +1/+1 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy that creature.)

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.

Cascading Cataracts

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

Sol Ring

The Prismatic Bridge

At the beginning of your upkeep, reveal cards from the top of your library until you reveal a creature or planeswalker card. Put that card onto the battlefield and the rest on the bottom of your library in a random order.

Esika, God of the Tree

Vigilance
{T}: Add one mana of any color.
Other legendary creatures you control have vigilance and "{T}: Add one mana of any color."

Esika, God of the Tree // The Prismatic Bridge

Crystallized Serah

The first legendary creature spell you cast each turn costs {2} less to cast.
Legendary creatures you control get +2/+2.

Serah Farron

The first legendary creature spell you cast each turn costs {2} less to cast.
At the beginning of combat on your turn, if you control two or more other legendary creatures, you may transform Serah Farron.

Serah Farron // Crystallized Serah

Ancient Cornucopia

Whenever you cast a spell that's one or more colors, you may gain 1 life for each of that spell's colors. Do this only once each turn.
{T}: Add one mana of any color.

Civic Saber

Equipped creature gets +1/+0 for each of its colors.
Equip {1}

Maze Behemoth

Trample
Multicolored creatures you control have trample.

Shanid, Sleepers' Scourge

Menace
Other legendary creatures you control have menace.
Whenever you play a legendary land or cast a legendary spell, you draw a card and you lose 1 life.

Maze Abomination

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Multicolored creatures you control have deathtouch.

Gloryscale Viashino

Whenever you cast a multicolored spell, this creature gets +3/+3 until end of turn.