Crawling Barrens

{T}: Add {C}.
{4}: Put two +1/+1 counters on this land. Then you may have it become a 0/0 Elemental creature until end of turn. It's still a land.

Eldrazi Temple

{T}: Add {C}.
{T}: Add {C}{C}. Spend this mana only to cast colorless Eldrazi spells or activate abilities of colorless Eldrazi.

Urza's Incubator

As this artifact enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Urza's Tower

{T}: Add {C}. If you control an Urza's Mine and an Urza's Power-Plant, add {C}{C}{C} instead.

Tomb of the Spirit Dragon

{T}: Add {C}.
{2}, {T}: You gain 1 life for each colorless creature you control.

Zhulodok, Void Gorger

Colorless spells you cast from your hand with mana value 7 or greater have "Cascade, cascade." (When you cast one, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order. Then do it again.)

Mage-Ring Network

{T}: Add {C}.
{1}, {T}: Put a storage counter on this land.
{T}, Remove any number of storage counters from this land: Add {C} for each storage counter removed this way.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Fellwar Stone

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

Thespian's Stage

{T}: Add {C}.
{2}, {T}: This land becomes a copy of target land, except it has this ability.

Everflowing Chalice

Multikicker {2} (You may pay an additional {2} any number of times as you cast this spell.)
This artifact enters with a charge counter on it for each time it was kicked.
{T}: Add {C} for each charge counter on this artifact.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Treasure Vault

{T}: Add {C}.
{X}{X}, {T}, Sacrifice this land: Create X Treasure tokens.

Reliquary Tower

Geier Reach Sanitarium

{T}: Add {C}.
{2}, {T}: Each player draws a card, then discards a card.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Homeward Path

{T}: Add {C}.
{T}: Each player gains control of all creatures they own.

Guildless Commons

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {C}{C}.

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

Cloudpost

This land enters tapped.
{T}: Add {C} for each Locus on the battlefield.

Bonders' Enclave

{T}: Add {C}.
{3}, {T}: Draw a card. Activate only if you control a creature with power 4 or greater.

Urza's Workshop

{T}: Add {C}.
Metalcraft — {T}: Add {C} for each Urza's land you control. Activate only if you control three or more artifacts.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Zhalfirin Void

When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {C}.

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice this land: You may cast spells this turn as though they had flash.

Inventors' Fair

At the beginning of your upkeep, if you control three or more artifacts, you gain 1 life.
{T}: Add {C}.
{4}, {T}, Sacrifice Inventors' Fair: Search your library for an artifact card, reveal it, put it into your hand, then shuffle. Activate only if you control three or more artifacts.

Eye of Ugin

Colorless Eldrazi spells you cast cost {2} less to cast.
{7}, {T}: Search your library for a colorless creature card, reveal it, put it into your hand, then shuffle.

Urza's Power Plant

{T}: Add {C}. If you control an Urza's Mine and an Urza's Tower, add {C}{C} instead.

Witch's Clinic

{T}: Add {C}.
{2}, {T}: Target commander gains lifelink until end of turn.

Mirrorpool

This land enters tapped.
{T}: Add {C}.
{2}{C}, {T}, Sacrifice this land: Copy target instant or sorcery spell you control. You may choose new targets for the copy.
{4}{C}, {T}, Sacrifice this land: Create a token that's a copy of target creature you control.

Sanctum of Eternity

{T}: Add {C}.
{2}, {T}: Return target commander you own from the battlefield to your hand. Activate only during your turn.

The Mycosynth Gardens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{X}, {T}: This land becomes a copy of target nontoken artifact you control with mana value X.

Sanctum of Ugin

{T}: Add {C}.
Whenever you cast a colorless spell with mana value 7 or greater, you may sacrifice this land. If you do, search your library for a colorless creature card, reveal it, put it into your hand, then shuffle.

High Market

{T}: Add {C}.
{T}, Sacrifice a creature: You gain 1 life.

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Shrine of the Forsaken Gods

{T}: Add {C}.
{T}: Add {C}{C}. Spend this mana only to cast colorless spells. Activate only if you control seven or more lands.

Zoetic Cavern

{T}: Add {C}.
Morph {2} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Tyrite Sanctum

{T}: Add {C}.
{2}, {T}: Target legendary creature becomes a God in addition to its other types. Put a +1/+1 counter on it.
{4}, {T}, Sacrifice this land: Put an indestructible counter on target God.

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Sol Ring

Wastes

Urza's Factory

{T}: Add {C}.
{7}, {T}: Create a 2/2 colorless Assembly-Worker artifact creature token.

Strip Mine

{T}: Add {C}.
{T}, Sacrifice this land: Destroy target land.

Ugin, the Ineffable

Colorless spells you cast cost {2} less to cast.
+1: Exile the top card of your library face down and look at it. Create a 2/2 colorless Spirit creature token. When that token leaves the battlefield, put the exiled card into your hand.
−3: Destroy target permanent that's one or more colors.

Scavenger Grounds

{T}: Add {C}.
{2}, {T}, Sacrifice a Desert: Exile all graveyards.

Mikokoro, Center of the Sea

{T}: Add {C}.
{2}, {T}: Each player draws a card.

Glimmerpost

When this land enters, you gain 1 life for each Locus on the battlefield.
{T}: Add {C}.

Urza's Mine

{T}: Add {C}. If you control an Urza's Power-Plant and an Urza's Tower, add {C}{C} instead.

Field of the Dead

This land enters tapped.
{T}: Add {C}.
Whenever this land or another land you control enters, if you control seven or more lands with different names, create a 2/2 black Zombie creature token.