Traverse the Outlands

Search your library for up to X basic land cards, where X is the greatest power among creatures you control. Put those cards onto the battlefield tapped, then shuffle.

Sea Gate

Sea Gate enters tapped.
As Sea Gate enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Maze's End

Maze's End enters tapped.
{T}: Add {C}.
{3}, {T}, Return Maze's End to its owner's hand: Search your library for a Gate card, put it onto the battlefield, then shuffle. If you control ten or more Gates with different names, you win the game.

Destiny Spinner

Creature and enchantment spells you control can't be countered.
{3}{G}: Target land you control becomes an X/X Elemental creature with trample and haste until end of turn, where X is the number of enchantments you control. It's still a land.

Baldur's Gate

{T}: Add {C}.
{2}, {T}: Add X mana of any one color, where X is the number of other Gates you control.

Gond Gate

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

Gateway Plaza

Gateway Plaza enters tapped.
When Gateway Plaza enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Heap Gate

{T}: Add {C}.
{1}, {T}: Add one mana of any color.
{1}, {T}, Tap an untapped Gate you control: Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

The Black Gate

As The Black Gate enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.
{1}{B}, {T}: Choose a player with the most life or tied for most life. Target creature can't be blocked by creatures that player controls this turn.

Thran Portal

Thran Portal enters tapped unless you control two or fewer other lands.
As Thran Portal enters, choose a basic land type.
Thran Portal is the chosen type in addition to its other types.
Mana abilities of Thran Portal cost an additional 1 life to activate.

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.

Tempt with Discovery

Tempting offer — Search your library for a land card and put it onto the battlefield. Each opponent may search their library for a land card and put it onto the battlefield. For each opponent who searches a library this way, search your library for a land card and put it onto the battlefield. Then each player who searched a library this way shuffles.

Plaza of Harmony

When Plaza of Harmony enters, if you control two or more Gates, you gain 3 life.
{T}: Add {C}.
{T}: Add one mana of any type that a Gate you control could produce.

Dimir Guildgate

Dimir Guildgate enters tapped.
{T}: Add {U} or {B}.

Golgari Guildgate

Golgari Guildgate enters tapped.
{T}: Add {B} or {G}.

Black Dragon Gate

Black Dragon Gate enters tapped.
As Black Dragon Gate enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Manor Gate

Manor Gate enters tapped.
As Manor Gate enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

Basilisk Gate

{T}: Add {C}.
{2}, {T}: Target creature gets +X/+X until end of turn, where X is the number of Gates you control. Activate only as a sorcery.

Rootpath Purifier

Lands you control and land cards in your library are basic.

Spelunking

When Spelunking enters, draw a card, then you may put a land card from your hand onto the battlefield. If you put a Cave onto the battlefield this way, you gain 4 life.
Lands you control enter untapped.

Simic Guildgate

Simic Guildgate enters tapped.
{T}: Add {G} or {U}.

Open the Gates

Search your library for a basic land card or Gate card, reveal it, put it 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.

Nine-Fingers Keene

Menace
Ward—Pay 9 life.
Whenever Nine-Fingers Keene deals combat damage to a player, look at the top nine cards of your library. You may put a Gate card from among them onto the battlefield. Then if you control nine or more Gates, put the rest into your hand. Otherwise, put the rest on the bottom of your library in a random order.

Oracle of Mul Daya

You may play an additional land on each of your turns.
Play with the top card of your library revealed.
You may play lands from the top of your library.

Navigation Orb

{2}, {T}, Sacrifice Navigation Orb: Search your library for up to two basic land cards and/or Gate cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.