Urza's Mine

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

Darksteel Citadel

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard this card: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Urza's Cave

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

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.

Kappa Cannoneer

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Ward {4}
Whenever this creature or another artifact you control enters, put a +1/+1 counter on this creature. It can't be blocked this turn.

Tolaria West

This land enters tapped.
{T}: Add {U}.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with mana value 0, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

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.

Skyscanner

Flying
When this creature enters, draw a card.

Vantress Visions

Copy target activated or triggered ability you control. You may choose new targets for the copy.

Virtue of Knowledge

If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Virtue of Knowledge // Vantress Visions

Unwinding Clock

Untap all artifacts you control during each other player's untap step.

Circuit Mender

When this creature enters, you gain 2 life.
When this creature leaves the battlefield, draw a card.

Coral Atoll

This land enters tapped.
When this land enters, sacrifice it unless you return an untapped Island you control to its owner's hand.
{T}: Add {C}{U}.

Thought Monitor

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When this creature enters, draw two cards.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Seat of the Synod

Reliquary Tower

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

Island

Ancient Tomb

{T}: Add {C}{C}. This land deals 2 damage to you.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice this land: Put your commander into your hand from the command zone.

Mistrise Village

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {U}.
{U}, {T}: The next spell you cast this turn can't be countered.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Archway of Innovation

This land enters tapped unless you control an Island.
{T}: Add {U}.
{U}, {T}: The next spell you cast this turn has improvise. (Your artifacts can help cast that spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)

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.

Spellskite

{U/P}: Change a target of target spell or ability to this creature. ({U/P} can be paid with either {U} or 2 life.)

Urza's Power Plant

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

Encroaching Mycosynth

Nonland permanents you control are artifacts in addition to their other types. The same is true for permanent spells you control and nonland permanent cards you own that aren't on the battlefield.

Urza's Tower

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

Academy Ruins

{T}: Add {C}.
{1}{U}, {T}: Put target artifact card from your graveyard on top of your library.

Temple of the False God

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

Basalt Monolith

This artifact doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap this artifact.

Jin-Gitaxias, Progress Tyrant

Whenever you cast an artifact, instant, or sorcery spell, copy that spell. You may choose new targets for the copy. This ability triggers only once each turn. (A copy of a permanent spell becomes a token.)
Whenever an opponent casts an artifact, instant, or sorcery spell, counter that spell. This ability triggers only once each turn.

Sicarian Infiltrator

Flash
Squad {2} (As an additional cost to cast this spell, you may pay {2} any number of times. When this creature enters, create that many tokens that are copies of it.)
Benediction of the Omnissiah — When this creature enters, draw a card.

Starfield Vocalist

If a permanent entering the battlefield causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Warp {1}{U} (You may cast this card from your hand for its warp cost. Exile this creature at the beginning of the next end step, then you may cast it from exile on a later turn.)

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Phyrexian Metamorph

({U/P} can be paid with either {U} or 2 life.)
You may have this creature enter as a copy of any artifact or creature on the battlefield, except it's an artifact in addition to its other types.

War Room

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

Urza's Saga

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — This Saga gains "{T}: Add {C}."
II — This Saga gains "{2}, {T}: Create a 0/0 colorless Construct artifact creature token with 'This token gets +1/+1 for each artifact you control.'"
III — Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.

Castle Vantress

This land enters tapped unless you control an Island.
{T}: Add {U}.
{2}{U}{U}, {T}: Scry 2.

Buried Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice this land: Return target artifact card from your graveyard to your hand.