Explore the Underdark

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.
You take the initiative.

Sol Ring

Command Tower

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

Prairie Stream

({T}: Add {W} or {U}.)
This land enters tapped unless you control two or more basic lands.

Smoldering Marsh

({T}: Add {B} or {R}.)
This land enters tapped unless you control two or more basic lands.

Mountain

Forest

Canopy Vista

({T}: Add {G} or {W}.)
This land enters tapped unless you control two or more basic lands.

Exotic Orchard

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

Island

Swamp

Cinder Glade

({T}: Add {R} or {G}.)
This land enters tapped unless you control two or more basic lands.

Sunken Hollow

({T}: Add {U} or {B}.)
This land enters tapped unless you control two or more basic lands.

Gruul Guildgate

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

Plains

Azorius Guildgate

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

Selesnya Guildgate

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

Gond Gate

Gates you control enter untapped.
{T}: Add {C}.
{T}: Add one mana of any color that a Gate you control could produce.

Farseek

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

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.

Circuitous Route

Search your library for up to two basic land cards and/or Gate cards, put them onto the battlefield tapped, then shuffle.

Fellwar Stone

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Khalni Heart Expedition

Landfall — Whenever a land you control enters, you may put a quest counter on this enchantment.
Remove three quest counters from this enchantment and sacrifice it: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Fertile Ground

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional one mana of any color.

Dimir Guildgate

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

Orzhov Guildgate

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

Arcane Signet

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Kodama's Reach

Izzet Guildgate

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

Rampant Growth

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

Boros Guildgate

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

Rakdos Guildgate

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

Open the Gates

Search your library for a basic land card or Gate card, reveal it, put it into your hand, then shuffle.

Simic Guildgate

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