Titan's Presence

As an additional cost to cast this spell, reveal a colorless creature card from your hand.
Exile target creature if its power is less than or equal to the revealed card's power.

Sol Ring

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Sanctum of Ugin

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

Sojourner's Companion

Affinity for artifacts
Artifact landcycling {2} ({2}, Discard this card: Search your library for an artifact land card, reveal it, put it into your hand, then shuffle.)

Zhalfirin Void

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

Temple of the False God

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

War Room

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

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.

Tomb of the Spirit Dragon

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

Bonders' Enclave

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

Mage-Ring Network

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

Mycosynth Golem

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Artifact creature spells you cast have affinity for artifacts. (They cost {1} less to cast for each artifact you control.)

Myr Enforcer

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Rogue's Passage

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

Reliquary Tower

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

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.

Palladium Myr

Blinkmoth Urn

At the beginning of each player's first main phase, if Blinkmoth Urn is untapped, that player adds {C} for each artifact they control.

Forsaken Monument

Colorless creatures you control get +2/+2.
Whenever you tap a permanent for {C}, add an additional {C}.
Whenever you cast a colorless spell, you gain 2 life.

Radiant Fountain

When Radiant Fountain enters, you gain 2 life.
{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.

Arch of Orazca

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
{T}: Add {C}.
{5}, {T}: Draw a card. Activate only if you have the city's blessing.

Darksteel Juggernaut

Indestructible
Darksteel Juggernaut's power and toughness are each equal to the number of artifacts you control.
Darksteel Juggernaut attacks each combat if able.

Shambling Suit

Shambling Suit's power is equal to the number of artifacts and/or enchantments you control.

Frogmite

Thespian's Stage

{T}: Add {C}.
{2}, {T}: Thespian's Stage becomes a copy of target land, except it has this ability.

Dreamstone Hedron

{T}: Add {C}{C}{C}.
{3}, {T}, Sacrifice Dreamstone Hedron: Draw three cards.

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Darksteel Citadel

Buried Ruin

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

Urza's Power Plant

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

Urza's Tower

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