Getting

Prismatic Ending

Converge — Exile target nonland permanent if its mana value is less than or equal to the number of colors of mana spent to cast this spell.

General Ferrous Rokiric

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

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}.

Radiant Epicure

Converge — When this creature enters, each opponent loses X life and you gain X life, where X is the number of colors of mana spent to cast this spell.

Ramos, Dragon Engine

Flying
Whenever you cast a spell, put a +1/+1 counter on Ramos 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.

Sweep the Skies

Converge — Create a 1/1 colorless Thopter artifact creature token with flying for each color of mana spent to cast this spell.

Planewide Celebration

Choose four. You may choose the same mode more than once.
• Create a 2/2 Citizen creature token that's all colors.
• Return target permanent card from your graveyard to your hand.
• Proliferate.
• You gain 4 life.

Leyline Binding

Flash
Domain — This spell costs {1} less to cast for each basic land type among lands you control.
When this enchantment enters, exile target nonland permanent an opponent controls until this enchantment leaves the battlefield.

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.

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.

Radiant Flames

Converge — Radiant Flames deals X damage to each creature, where X is the number of colors of mana spent to cast this spell.

Dragonfire Blade

Equipped creature gets +2/+2 and has hexproof from monocolored.
Equip {4}. This ability costs {1} less to activate for each color of the creature it targets.

Courier's Briefcase

When this artifact enters, create a 1/1 green and white Citizen creature token.
{T}, Sacrifice this artifact: Add one mana of any color.
{W}{U}{B}{R}{G}, {T}, Sacrifice this artifact: Draw three cards.

Kaleidoscorch

Converge — Kaleidoscorch deals X damage to any target, where X is the number of colors of mana spent to cast this spell.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

Leyline of the Guildpact

If this card 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.