Izzet Signet

Sol Ring

Clifftop Retreat

Clifftop Retreat enters the battlefield tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Command Tower

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

Aragorn, the Uniter

Whenever you cast a white spell, create a 1/1 white Human Soldier creature token.
Whenever you cast a blue spell, scry 2.
Whenever you cast a red spell, Aragorn, the Uniter deals 3 damage to target opponent.
Whenever you cast a green spell, target creature gets +4/+4 until end of turn.

Arcane Signet

Archivist of Gondor

When your commander deals combat damage to a player, if there is no monarch, you become the monarch.
At the beginning of the monarch's end step, that player draws a card.

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. Battlefield Forge deals 1 damage to you.

Azorius Signet

Aragorn, King of Gondor

Vigilance, lifelink
When Aragorn, King of Gondor enters the battlefield, you become the monarch.
Whenever Aragorn attacks, up to one target creature can't block this turn. If you're the monarch, creatures can't block this turn.

Deserted Beach

Deserted Beach enters the battlefield tapped unless you control two or more other lands.
{T}: Add {W} or {U}.

Sundown Pass

Sundown Pass enters the battlefield tapped unless you control two or more other lands.
{T}: Add {R} or {W}.

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. Shivan Reef deals 1 damage to you.

Boros Signet

Prairie Stream

({T}: Add {W} or {U}.)
Prairie Stream enters the battlefield tapped unless you control two or more basic lands.

Glacial Fortress

Glacial Fortress enters the battlefield tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Hallowed Fountain

({T}: Add {W} or {U}.)
As Hallowed Fountain enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Sacred Foundry

({T}: Add {R} or {W}.)
As Sacred Foundry enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.

Raugrin Triome

({T}: Add {U}, {R}, or {W}.)
Raugrin Triome enters the battlefield tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Sulfur Falls

Sulfur Falls enters the battlefield tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Stormcarved Coast

Stormcarved Coast enters the battlefield tapped unless you control two or more other lands.
{T}: Add {U} or {R}.