Eluge, the Shoreless Sea

Eluge's power and toughness are each equal to the number of Islands you control.
Whenever Eluge enters or attacks, put a flood counter on target land. It's an Island in addition to its other types for as long as it has a flood counter on it.
The first instant or sorcery spell you cast each turn costs {U} (or {1}) less to cast for each land you control with a flood counter on it.

Kavu Recluse

{T}: Target land becomes a Forest until end of turn.

Soul of New Phyrexia

Trample
{5}: Permanents you control gain indestructible until end of turn.
{5}, Exile Soul of New Phyrexia from your graveyard: Permanents you control gain indestructible until end of turn.

Shimmering Mirage

Target land becomes the basic land type of your choice until end of turn.
Draw a card.

Lingering Mirage

Enchant land
Enchanted land is an Island.
Cycling {2} ({2}, Discard this card: Draw a card.)

Carpet of Flowers

At the beginning of each of your main phases, if you haven't added mana with this ability this turn, you may add X mana of any one color, where X is the number of Islands target opponent controls.

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.

Mind Bend

Change the text of target permanent by replacing all instances of one color word with another or one basic land type with another. (For example, you may change "nonblack creature" to "nongreen creature" or "forestwalk" to "islandwalk." This effect lasts indefinitely.)

Yavimaya Dryad

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
When Yavimaya Dryad enters, you may search your library for a Forest card, put it onto the battlefield tapped under target player's control, then shuffle.

Silverbluff Bridge

Silverbluff Bridge enters tapped.
Indestructible
{T}: Add {U} or {R}.

Command Tower

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

Volcanic Eruption

Destroy X target Mountains. Volcanic Eruption deals damage to each creature and each player equal to the number of Mountains put into a graveyard this way.

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Nylea's Presence

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

Tanglepool Bridge

Tanglepool Bridge enters tapped.
Indestructible
{T}: Add {G} or {U}.

Tundra Kavu

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

Slagwoods Bridge

Slagwoods Bridge enters tapped.
Indestructible
{T}: Add {R} or {G}.

Harbinger of the Seas

Floodchaser

Floodchaser enters with six +1/+1 counters on it.
Floodchaser can't attack unless defending player controls an Island.
{U}, Remove a +1/+1 counter from Floodchaser: Target land becomes an Island until end of turn.

Dream Thrush

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

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.

Unstable Frontier

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

Streambed Aquitects

{T}: Target Merfolk creature gets +1/+1 and gains islandwalk until end of turn. (It can't be blocked as long as defending player controls an Island.)
{T}: Target land becomes an Island until end of turn.

Magical Hack

Change the text of target spell or permanent by replacing all instances of one basic land type with another. (For example, you may change "swampwalk" to "plainswalk." This effect lasts indefinitely.)

Arcane Signet

Xolatoyac, the Smiling Flood

Whenever Xolatoyac, the Smiling Flood enters or attacks, put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it.
At the beginning of your end step, untap each permanent you control with a counter on it.

Elsewhere Flask

When Elsewhere Flask enters, draw a card.
Sacrifice Elsewhere Flask: Choose a basic land type. Each land you control becomes that type until end of turn.

Whim of Volrath

Buyback {2} (You may pay an additional {2} as you cast this spell. If you do, put this card into your hand as it resolves.)
Change the text of target permanent by replacing all instances of one color word with another or one basic land type with another until end of turn. (For example, you may change "nonred creature" to "nongreen creature" or "plainswalk" to "swampwalk.")

Urborg, Tomb of Yawgmoth

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

The Flood of Mars

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Water Always Wins — Whenever The Flood of Mars attacks, put a flood counter on another target creature or land. If it's a creature, it becomes a copy of The Flood of Mars. If it's a land, it becomes an Island in addition to its other types.

Nature's Wrath

At the beginning of your upkeep, sacrifice Nature's Wrath unless you pay {G}.
Whenever a player puts an Island or blue permanent onto the battlefield, that player sacrifices an Island or blue permanent of their choice.
Whenever a player puts a Swamp or black permanent onto the battlefield, that player sacrifices a Swamp or black permanent of their choice.

Tsunami

Fellwar Stone

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

Moonbow Illusionist

Flying
{2}, Return a land you control to its owner's hand: Target land becomes the basic land type of your choice until end of turn.

Darksteel Garrison

Fortified land has indestructible.
Whenever fortified land becomes tapped, target creature gets +1/+1 until end of turn.
Fortify {3} ({3}: Attach to target land you control. Fortify only as a sorcery. This card enters unattached and stays on the battlefield if the land leaves.)

Phantasmal Terrain

Enchant land
As Phantasmal Terrain enters, choose a basic land type.
Enchanted land is the chosen type.

Crystal Spray

Change the text of target spell or permanent by replacing all instances of one color word with another or one basic land type with another until end of turn.
Draw a card.

Frozen Aether

Artifacts, creatures, and lands your opponents control enter tapped.

Spectral Shift

Choose one —
• Change the text of target spell or permanent by replacing all instances of one basic land type with another. (This effect lasts indefinitely.)
• Change the text of target spell or permanent by replacing all instances of one color word with another. (This effect lasts indefinitely.)
Entwine {2} (Choose both if you pay the entwine cost.)

Reef Shaman

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

Stormtide Leviathan

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
All lands are Islands in addition to their other types.
Creatures without flying or islandwalk can't attack.

Yavimaya, Cradle of Growth

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

Taniwha

Trample
Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)
At the beginning of your upkeep, all lands you control phase out. (They phase in before you untap during your next untap step.)

Mountain

Flashfires

Illusionary Terrain

Cumulative upkeep {2} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
As Illusionary Terrain enters, choose two basic land types.
Basic lands of the first chosen type are the second chosen type.

Sol Ring

Darksteel Citadel

Tideshaper Mystic

{T}: Target land becomes the basic land type of your choice until end of turn. Activate only during your turn.

Aquitect's Will

Put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it. If you control a Merfolk, draw a card.

Tidal Warrior

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

Magus of the Moon

Sea's Claim

Enchant land (Target a land as you cast this. This card enters attached to that land.)
Enchanted land is an Island.

Omo, Queen of Vesuva

Whenever Omo, Queen of Vesuva enters or attacks, put an everything counter on each of up to one target land and up to one target creature.
Each land with an everything counter on it is every land type in addition to its other types.
Each nonland creature with an everything counter on it is every creature type.

Forest

Sea Snidd

Mystic Compass

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

Spreading Seas

Enchant land
When Spreading Seas enters, draw a card.
Enchanted land is an Island.

Song of the Dryads

Enchant permanent
Enchanted permanent is a colorless Forest land.

Trait Doctoring

Change the text of target permanent by replacing all instances of one color word with another or one basic land type with another until end of turn.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Vision Charm

Choose one —
• Target player mills four cards.
• Choose a land type and a basic land type. Each land of the first chosen type becomes the second chosen type until end of turn.
• Target artifact phases out. (While it's phased out, it's treated as though it doesn't exist. It phases in before its controller untaps during their next untap step.)

Boil

Mask of Intolerance

At the beginning of each player's upkeep, if there are four or more basic land types among lands that player controls, Mask of Intolerance deals 3 damage to that player.

Inkwell Leviathan

Trample
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Shroud (This creature can't be the target of spells or abilities.)

Jinx

Target land becomes the basic land type of your choice until end of turn.
Draw a card at the beginning of the next turn's upkeep.

Boiling Seas

Blood Moon

Choke

Islands don't untap during their controllers' untap steps.

Convincing Mirage

Enchant land
As Convincing Mirage enters, choose a basic land type.
Enchanted land is the chosen type.

Cascading Cataracts

Indestructible
{T}: Add {C}.
{5}, {T}: Add five mana in any combination of colors.

Exotic Orchard

Sylvan Awakening

Until your next turn, all lands you control become 2/2 Elemental creatures with reach, indestructible, and haste. They're still lands.

Terraformer

{1}: Choose a basic land type. Each land you control becomes that type until end of turn.