Gush

You may return two Islands you control to their owner's hand rather than pay this spell's mana cost.
Draw two cards.

Enhanced Surveillance

You may look at an additional two cards each time you surveil.
Exile Enhanced Surveillance: Shuffle your graveyard into your library.

Ancient Silver Dragon

Flying
Whenever Ancient Silver Dragon deals combat damage to a player, roll a d20. Draw cards equal to the result. You have no maximum hand size for the rest of the game.

Farseek

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

Thassa's Oracle

When Thassa's Oracle enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Turn to Frog

Until end of turn, target creature loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Koma, Cosmos Serpent

This spell can't be countered.
At the beginning of each upkeep, create a 3/3 blue Serpent creature token named Koma's Coil.
Sacrifice another Serpent: Choose one —
• Tap target permanent. Its activated abilities can't be activated this turn.
• Koma, Cosmos Serpent gains indestructible until end of turn.

Lotus Cobra

Landfall — Whenever a land you control enters, add one mana of any color.

Loot, Exuberant Explorer

You may play an additional land on each of your turns.
{4}{G}{G}, {T}: Look at the top six cards of your library. You may reveal a creature card with mana value less than or equal to the number of lands you control from among them and put it onto the battlefield. Put the rest on the bottom in a random order.

Consecrated Sphinx

Flying
Whenever an opponent draws a card, you may draw two cards.

Felling Blow

Put a +1/+1 counter on target creature you control. Then that creature deals damage equal to its power to target creature an opponent controls.

Ancient Bronze Dragon

Flying
Whenever Ancient Bronze Dragon deals combat damage to a player, roll a d20. When you do, put X +1/+1 counters on each of up to two target creatures, where X is the result.

Exploration

You may play an additional land on each of your turns.

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.

Octomancer

Gift an Octopus (You may promise an opponent a gift as you cast this spell. If you do, when it enters, they create an 8/8 blue Octopus creature token.)
At the beginning of each end step, create a token that's a copy of target creature token that entered the battlefield this turn.

Counterspell

Pond Prophet

Whelming Wave

Return all creatures to their owners' hands except for Krakens, Leviathans, Octopuses, and Serpents.

Koma, World-Eater

This spell can't be countered.
Trample, ward {4}
Whenever Koma deals combat damage to a player, create four 3/3 blue Serpent creature tokens named Koma's Coil.

Irenicus's Vile Duplication

Create a token that's a copy of target creature you control, except the token has flying and it isn't legendary.

Aesi, Tyrant of Gyre Strait

You may play an additional land on each of your turns.
Landfall — Whenever a land you control enters, you may draw a card.

Swamp

Island

Reanimate

Put target creature card from a graveyard onto the battlefield under your control. You lose life equal to its mana value.

Craterhoof Behemoth

Haste
When Craterhoof Behemoth enters, creatures you control gain trample and get +X/+X until end of turn, where X is the number of creatures you control.

High Fae Trickster

Flash (You may cast this spell any time you could cast an instant.)
Flying
You may cast spells as though they had flash.

Force of Vigor

If it's not your turn, you may exile a green card from your hand rather than pay this spell's mana cost.
Destroy up to two target artifacts and/or enchantments.

Spark Double

You may have Spark Double enter as a copy of a creature or planeswalker you control, except it enters with an additional +1/+1 counter on it if it's a creature, it enters with an additional loyalty counter on it if it's a planeswalker, and it isn't legendary.

Uncharted Voyage

Target creature's owner puts it on their choice of the top or bottom of their library.
Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Rampant Frogantua

Trample
Rampant Frogantua gets +10/+10 for each player who has lost the game.
Whenever Rampant Frogantua deals combat damage to a player, you may mill that many cards. Put any number of land cards from among them onto the battlefield tapped.

Heroic Intervention

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

Wonder

Flying
As long as Wonder is in your graveyard and you control an Island, creatures you control have flying.

Forest

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Spore Frog

Sacrifice Spore Frog: Prevent all combat damage that would be dealt this turn.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Old Gnawbone

Flying
Whenever a creature you control deals combat damage to a player, create that many Treasure tokens.

Delighted Halfling

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell, and that spell can't be countered.

Glarb, Calamity's Augur

Deathtouch
You may look at the top card of your library any time.
You may play lands and cast spells with mana value 4 or greater from the top of your library.
{T}: Surveil 2.

The Gitrog, Ravenous Ride

Trample, haste
Whenever The Gitrog, Ravenous Ride deals combat damage to a player, you may sacrifice a creature that saddled it this turn. If you do, draw X cards, then put up to X land cards from your hand onto the battlefield tapped, where X is the sacrificed creature's power.
Saddle 1

Poison Dart Frog

Reach
{T}: Add one mana of any color.
{2}: Poison Dart Frog gains deathtouch until end of turn.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

Hedge Shredder

Whenever Hedge Shredder attacks, you may mill two cards.
Whenever one or more land cards are put into your graveyard from your library, put them onto the battlefield tapped.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)