Decanter of Endless Water

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

Growth Spiral

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

Exotic Orchard

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

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 deals 3 damage to target opponent.
Whenever you cast a green spell, target creature gets +4/+4 until end of turn.

Forest

Plains

Omnath, Locus of Creation

When Omnath enters, draw a card.
Landfall — Whenever a land you control enters, you gain 4 life if this is the first time this ability has resolved this turn. If it's the second time, add {R}{G}{W}{U}. If it's the third time, Omnath deals 4 damage to each opponent and each planeswalker you don't control.

Manamorphose

Add two mana in any combination of colors.
Draw a card.

Birds of Paradise

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.

Mountain

Tome of the Guildpact

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

Sol Ring

Command Tower

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

Evolving Wilds

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

Commander's Sphere

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

General Ferrous Rokiric

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

Noble Hierarch

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
{T}: Add {G}, {W}, or {U}.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Endless Detour

The owner of target spell, nonland permanent, or card in a graveyard puts it on their choice of the top or bottom of their library.

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.)

Arcane Signet

Island

Prizefight

Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)
Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Delighted Halfling

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell, and that spell can't be countered.

Chromatic Lantern

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

Myriad Landscape

This land enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice this land: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Cabaretti Charm

Choose one —
• Cabaretti Charm deals damage equal to the number of creatures you control to target creature or planeswalker.
• Creatures you control get +1/+1 and gain trample until end of turn.
• Create two 1/1 green and white Citizen creature tokens.