Urza's Tower

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

Scampering Surveyor

When this creature enters, search your library for a basic land card or Cave card, put it onto the battlefield tapped, then shuffle.

Urza's Power Plant

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

Trenchpost

{T}: Add {C}.
{3}, {T}: Target player mills a card for each Locus you control.

Glimmerpost

When this land enters, you gain 1 life for each Locus on the battlefield.
{T}: Add {C}.

Expedition Map

{2}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Planar Nexus

This land is every nonbasic land type. (Nonbasic land types include Cave, Desert, Gate, Lair, Locus, Mine, Power-Plant, Sphere, Tower, and Urza's.)
{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Urza's Mine

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

Urza's Workshop

{T}: Add {C}.
Metalcraft — {T}: Add {C} for each Urza's land you control. Activate only if you control three or more artifacts.

Cloudpost

This land enters tapped.
{T}: Add {C} for each Locus on the battlefield.

Vesuva

You may have this land enter tapped as a copy of any land on the battlefield.

Urza's Cave

{T}: Add {C}.
{3}, {T}, Sacrifice this land: Search your library for a land card, put it onto the battlefield tapped, then shuffle.

World Map

{1}, {T}, Sacrifice this artifact: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.
{3}, {T}, Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.