Maze Behemoth

Trample
Multicolored creatures you control have trample.

Nishoba Brawler

Trample
Domain — Nishoba Brawler's power is equal to the number of basic land types among lands you control.

Magnigoth Treefolk

Domain — For each basic land type among lands you control, Magnigoth Treefolk has landwalk of that type. (It can't be blocked as long as defending player controls a land of that type.)

Suncrusher

Sunburst (This enters with a +1/+1 counter on it for each color of mana spent to cast it.)
{4}, {T}, Remove a +1/+1 counter from Suncrusher: Destroy target creature.
{2}, Remove a +1/+1 counter from Suncrusher: Return Suncrusher to its owner's hand.

Engineered Explosives

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
{2}, Sacrifice Engineered Explosives: Destroy each nonland permanent with mana value equal to the number of charge counters on Engineered Explosives.

Territorial Maro

Domain — Territorial Maro's power and toughness are each equal to twice the number of basic land types among lands you control.

Scrapbasket

{1}: Scrapbasket becomes all colors until end of turn.

Yavimaya Sojourner

Domain — This spell costs {1} less to cast for each basic land type among lands you control.

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.)

Opaline Bracers

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
Equipped creature gets +X/+X, where X is the number of charge counters on Opaline Bracers.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Solarion

Sunburst (This enters with a +1/+1 counter on it for each color of mana spent to cast it.)
{T}: Double the number of +1/+1 counters on Solarion.

Distorting Lens

{T}: Target permanent becomes the color of your choice until end of turn.

Llanowar Greenwidow

Reach, trample
Domain — {7}{G}: Return Llanowar Greenwidow from your graveyard to the battlefield tapped. It gains "If this permanent would leave the battlefield, exile it instead of putting it anywhere else." This ability costs {1} less to activate for each basic land type among lands you control.

The Weatherseed Treaty

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
II — Create a 1/1 green Saproling creature token.
III — Domain — Target creature you control gets +X/+X and gains trample until end of turn, where X is the number of basic land types among lands you control.

Spore Burst

Domain — Create a 1/1 green Saproling creature token for each basic land type among lands you control.

Lunar Avenger

Sunburst (This enters with a +1/+1 counter on it for each color of mana spent to cast it.)
Remove a +1/+1 counter from Lunar Avenger: Lunar Avenger gains your choice of flying, first strike, or haste until end of turn.

Prismatic Geoscope

Prismatic Geoscope enters tapped.
Domain — {T}: Add X mana in any combination of colors, where X is the number of basic land types among lands you control.

Mechtitan Core

{5}, Exile Mechtitan Core and four other artifact creatures and/or Vehicles you control: Create Mechtitan, a legendary 10/10 Construct artifact creature token with flying, vigilance, trample, lifelink, and haste that's all colors. When that token leaves the battlefield, return all cards exiled with Mechtitan Core except Mechtitan Core to the battlefield tapped under their owners' control.
Crew 2

Baton of Courage

Flash
Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
Remove a charge counter from Baton of Courage: Target creature gets +1/+1 until end of turn.

Obsidian Obelisk

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

Glinting Creeper

Converge — Glinting Creeper enters with two +1/+1 counters on it for each color of mana spent to cast it.
Glinting Creeper can't be blocked by creatures with power 2 or less.

Pentad Prism

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
Remove a charge counter from Pentad Prism: Add one mana of any color.

Bloom Tender

{T}: For each color among permanents you control, add one mana of that color.

Etched Oracle

Sunburst (This enters with a +1/+1 counter on it for each color of mana spent to cast it.)
{1}, Remove four +1/+1 counters from Etched Oracle: Target player draws three cards.

Glass of the Guildpact

Multicolored creatures you control get +1/+1.

Infused Arrows

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
{T}, Remove X charge counters from Infused Arrows: Target creature gets -X/-X until end of turn.

Sisay's Ring

Clearwater Goblet

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
At the beginning of your upkeep, you may gain life equal to the number of charge counters on Clearwater Goblet.

Great Hall of the Citadel

{T}: Add {C}.
{1}, {T}: Add two mana in any combination of colors. Spend this mana only to cast legendary spells.

Heliophial

Sunburst (This enters with a charge counter on it for each color of mana spent to cast it.)
{2}, Sacrifice Heliophial: It deals damage equal to the number of charge counters on it to any target.

Rampaging Monument

Trample
Rampaging Monument enters with three +1/+1 counters on it.
Whenever you cast a multicolored spell, put a +1/+1 counter on Rampaging Monument.

Sawtooth Thresher

Sunburst (This enters with a +1/+1 counter on it for each color of mana spent to cast it.)
Remove two +1/+1 counters from Sawtooth Thresher: Sawtooth Thresher gets +4/+4 until end of turn.

Power Armor

Domain — {3}, {T}: Target creature gets +1/+1 until end of turn for each basic land type among lands you control.

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.

Arcbound Wanderer

Modular—Sunburst (This creature enters with a +1/+1 counter on it for each color of mana spent to cast it. When it dies, you may put its +1/+1 counters on target artifact creature.)

Woodland Wanderer

Vigilance, trample
Converge — Woodland Wanderer enters with a +1/+1 counter on it for each color of mana spent to cast it.

Briar Hydra

Trample
Domain — Whenever Briar Hydra deals combat damage to a player, put X +1/+1 counters on target creature you control, where X is the number of basic land types among lands you control.

Skyreach Manta

Sunburst (This enters with a +1/+1 counter on it for each color of mana spent to cast it.)
Flying

Might of Alara

Domain — Target creature gets +1/+1 until end of turn for each basic land type among lands you control.

Tome of the Guildpact

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

Tromp the Domains

Domain — Until end of turn, creatures you control gain trample and get +1/+1 for each basic land type among lands you control.

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.

Jodah's Codex

Domain — {5}, {T}: Draw a card. This ability costs {1} less to activate for each basic land type among lands you control.

Scion of Draco

Domain — This spell costs {2} less to cast for each basic land type among lands you control.
Flying
Each creature you control has vigilance if it's white, hexproof if it's blue, lifelink if it's black, first strike if it's red, and trample if it's green.

Guildmages' Forum

{T}: Add {C}.
{1}, {T}: Add one mana of any color. If that mana is spent on a multicolored creature spell, that creature enters with an additional +1/+1 counter on it.

Harvester Druid

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

Slimefoot's Survey

Domain — Search your library for up to two land cards that each have a basic land type, put them onto the battlefield tapped, then shuffle. Look at the top X cards of your library, where X is the number of basic land types among lands you control. Put up to one of them on top of your library and the rest on the bottom of your library in a random order.

Gaea's Might

Tajuru Stalwart

Converge — Tajuru Stalwart enters with a +1/+1 counter on it for each color of mana spent to cast it.

Herd Migration

Domain — Create a 3/3 green Beast creature token for each basic land type among lands you control.
{1}{G}, Discard Herd Migration: Search your library for a basic land card, reveal it, put it into your hand, then shuffle. You gain 3 life.

Spinal Parasite

Sunburst (This enters with a +1/+1 counter on it for each color of mana spent to cast it.)
Remove two +1/+1 counters from Spinal Parasite: Remove a counter from target permanent.

Zenith Chronicler

Whenever a player casts their first multicolored spell each turn, each other player draws a card.

Infuse with the Elements

Converge — Put X +1/+1 counters on target creature, where X is the number of colors of mana spent to cast this spell. That creature gains trample until end of turn.

Verdant Eidolon

{G}, Sacrifice Verdant Eidolon: Add three mana of any one color.
Whenever you cast a multicolored spell, you may return Verdant Eidolon from your graveyard to your hand.

Stratadon

Domain — This spell costs {1} less to cast for each basic land type among lands you control.
Trample

Scuttlemutt

{T}: Add one mana of any color.
{T}: Target creature becomes the color or colors of your choice until end of turn.

Crystalline Crawler

Converge — Crystalline Crawler enters with a +1/+1 counter on it for each color of mana spent to cast it.
Remove a +1/+1 counter from Crystalline Crawler: Add one mana of any color.
{T}: Put a +1/+1 counter on Crystalline Crawler.

Forest

Arcane Signet

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

Jade Leech

Green spells you cast cost {G} more to cast.

Matca Rioters

Domain — Matca Rioters's power and toughness are each equal to the number of basic land types among lands you control.

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.

Wandering Stream

Domain — You gain 2 life for each basic land type among lands you control.

Manaforce Mace

Domain — Equipped creature gets +1/+1 for each basic land type among lands you control.
Equip {3}

Sunbathing Rootwalla

Domain — {3}{G}: Until end of turn, Sunbathing Rootwalla gets +1/+1 for each basic land type among lands you control. Activate only once each turn.

Suntouched Myr

Sunburst (This enters with a +1/+1 counter on it for each color of mana spent to cast it.)