Arcane Signet

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

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Burgeoning

Whenever an opponent plays a land, you may put a land card from your hand onto the battlefield.

Azorius Signet

Exploration

You may play an additional land on each of your turns.

Orzhov Signet

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}.

Rakdos Signet

Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Dimir Signet

Gruul Signet

Simic Signet

Boros Signet

Golgari Signet

Fellwar Stone

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

Izzet Signet

Search for Tomorrow

Search your library for a basic land card, put it onto the battlefield, then shuffle.
Suspend 2—{G} (Rather than cast this card from your hand, you may pay {G} 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.)

Selesnya Signet

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Sol Ring

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.