Aragorn, King of Gondor

Vigilance, lifelink
When Aragorn enters, you become the monarch.
Whenever Aragorn attacks, up to one target creature can't block this turn. If you're the monarch, creatures can't block this turn.

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.

City on Fire

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
If a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Flockchaser Phantom

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Flying, vigilance
Whenever this creature attacks, the next spell you cast this turn has convoke.

General Ferrous Rokiric

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

Katilda and Lier

Whenever you cast a Human spell, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (You may cast that card from your graveyard for its flashback cost. Then exile it.)

Mondrak, Glory Dominus

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
{1}{W/P}{W/P}, Sacrifice two other artifacts and/or creatures: Put an indestructible counter on Mondrak. ({W/P} can be paid with either {W} or 2 life.)

Jinnie Fay, Jetmir's Second

If you would create one or more tokens, you may instead create that many 2/2 green Cat creature tokens with haste or that many 3/1 green Dog creature tokens with vigilance.

Wildfire Awakener

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
When this creature enters, create X 1/1 red Elemental creature tokens with "Whenever this token becomes tapped, it deals 1 damage to target player."

Hero of Precinct One

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

Hour of Reckoning

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Destroy all nontoken creatures.

March of the Multitudes

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Create X 1/1 white Soldier creature tokens with lifelink.

Parallel Lives

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Guildpact Paragon

Whenever you cast a spell that's exactly two colors, look at the top six cards of your library. You may reveal a card that's exactly two colors from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Invasion of Ravnica

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When this Siege enters, exile target nonland permanent an opponent controls that isn't exactly two colors.

Invasion of Ravnica // Guildpact Paragon

Urza's Filter

Multicolored spells cost {2} less to cast.

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.)

Kasla, the Broken Halo

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Flying, vigilance, haste
Whenever you cast another spell that has convoke, scry 2, then draw a card.

Tome of the Guildpact

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

Aragorn, Company Leader

Whenever the Ring tempts you, if you chose a creature other than Aragorn as your Ring-bearer, put your choice of a counter from among first strike, vigilance, deathtouch, and lifelink on Aragorn.
Whenever you put one or more counters on Aragorn, put one of each of those kinds of counters on up to one other target creature.

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.

Aragorn and Arwen, Wed

Vigilance
Whenever Aragorn and Arwen enters or attacks, put a +1/+1 counter on each other creature you control. You gain 1 life for each other creature you control.

Saint Traft and Rem Karolus

Whenever Saint Traft and Rem Karolus becomes tapped, create a 1/1 red Human creature token if this is the first time this ability has resolved this turn. If it's the second time, create a 1/1 blue Spirit creature token with flying. If it's the third time, create a 4/4 white Angel creature token with flying.
Whenever you cast a spell that has convoke, untap Saint Traft and Rem Karolus.

Ghired, Conclave Exile

When Ghired enters, create a 4/4 green Rhino creature token with trample.
Whenever Ghired attacks, populate. The token enters tapped and attacking. (To populate, create a token that's a copy of a creature token you control.)

Neyali, Suns' Vanguard

Attacking tokens you control have double strike.
Whenever one or more tokens you control attack a player, exile the top card of your library. During any turn you attacked with a token, you may play that card.

Doubling Season

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent you control, it puts twice that many of those counters on that permanent instead.

Divine Visitation

If one or more creature tokens would be created under your control, that many 4/4 white Angel creature tokens with flying and vigilance are created instead.

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.