Simic Signet

Orzhov Guildgate

This land enters tapped.
{T}: Add {W} or {B}.

Marble Diamond

Marble Diamond enters tapped.
{T}: Add {W}.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Arcane Signet

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

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.

Sensei's Divining Top

{1}: Look at the top three cards of your library, then put them back in any order.
{T}: Draw a card, then put Sensei's Divining Top on top of its owner's library.

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Dimir Signet

Ancient Tomb

{T}: Add {C}{C}. Ancient Tomb deals 2 damage to you.

Azorius Guildgate

This land enters tapped.
{T}: Add {W} or {U}.

Field of the Dead

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

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Atraxa, Praetors' Voice

Flying, vigilance, deathtouch, lifelink
At the beginning of your end step, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Fellwar Stone

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

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Mana Vault

Mana Vault doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault.
At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you.
{T}: Add {C}{C}{C}.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Sky Diamond

Golgari Signet

Selesnya Signet

Rakdos Guildgate

This land enters tapped.
{T}: Add {B} or {R}.

Mana Crypt

At the beginning of your upkeep, flip a coin. If you lose the flip, Mana Crypt deals 3 damage to you.
{T}: Add {C}{C}.

Profane Tutor

Suspend 2—{1}{B} (Rather than cast this card from your hand, pay {1}{B} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search your library for a card, put that card into your hand, then shuffle.

Selesnya Guildgate

This land enters tapped.
{T}: Add {G} or {W}.

Dimir Guildgate

This land enters tapped.
{T}: Add {U} or {B}.

Moss Diamond

Moss Diamond enters tapped.
{T}: Add {G}.

Winter Orb

As long as Winter Orb is untapped, players can't untap more than one land during their untap steps.