Path to the Festival

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle. Then if there are three or more basic land types among lands you control, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)
Flashback {4}{G} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Unstable Frontier

{T}: Add {C}.
{T}: Target land you control becomes the basic land type of your choice until end of turn.

Nylea's Presence

Enchant land
When Nylea's Presence enters the battlefield, draw a card.
Enchanted land is every basic land type in addition to its other types.

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Jodah's Codex

Domain — {5}, {T}: Draw a card. This ability costs {1} less to activate for each basic land type among lands you control.

Territorial Kavu

Domain — Territorial Kavu's power and toughness are each equal to the number of basic land types among lands you control.
Whenever Territorial Kavu attacks, choose one —
• Discard a card. If you do, draw a card.
• Exile up to one target card from a graveyard.

Mystic Compass

{1}, {T}: Target land becomes the basic land type of your choice until end of turn.

Power Armor

Domain — {3}, {T}: Target creature gets +1/+1 until end of turn for each basic land type among lands you control.

Tundra Kavu

{T}: Target land becomes a Plains or an Island until end of turn.

Prismatic Omen

Lands you control are every basic land type in addition to their other types.

Nishoba Brawler

Trample
Domain — Nishoba Brawler's power is equal to the number of basic land types among lands you control.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Thran Portal

Thran Portal enters the battlefield tapped unless you control two or fewer other lands.
As Thran Portal enters the battlefield, 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.

Llanowar Greenwidow

Reach, trample
Domain — {7}{G}: Return Llanowar Greenwidow from your graveyard to the battlefield tapped. It gains "If this permanent would leave the battlefield, exile it instead of putting it anywhere else." This ability costs {1} less to activate for each basic land type among lands you control.

Radha, Coalition Warlord

Domain — Whenever Radha, Coalition Warlord becomes tapped, another target creature you control gets +X/+X until end of turn, where X is the number of basic land types among lands you control.

Collapsing Borders

Domain — At the beginning of each player's upkeep, that player gains 1 life for each basic land type among lands they control. Then Collapsing Borders deals 3 damage to that player.

Navigator's Compass

When Navigator's Compass enters the battlefield, you gain 3 life.
{T}: Until end of turn, target land you control becomes the basic land type of your choice in addition to its other types.

Lush Growth

Enchant land
Enchanted land is a Mountain, Forest, and Plains.

Spreading Algae

Enchant Swamp
When enchanted land becomes tapped, destroy it.
When Spreading Algae is put into a graveyard from the battlefield, return Spreading Algae to its owner's hand.

The Weatherseed Treaty

Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.)
I — Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
II — Create a 1/1 green Saproling creature token.
III — Domain — Target creature you control gets +X/+X and gains trample until end of turn, where X is the number of basic land types among lands you control.

Quicksilver Fountain

At the beginning of each player's upkeep, that player puts a flood counter on target non-Island land they control of their choice. That land is an Island for as long as it has a flood counter on it.
At the beginning of each end step, if all lands on the battlefield are Islands, remove all flood counters from them.