Tidespout Tyrant

Flying
Whenever you cast a spell, return target permanent to its owner's hand.

Sky Diamond

Sky Diamond enters the battlefield tapped.
{T}: Add {U}.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Back to Basics

Nonbasic lands don't untap during their controllers' untap steps.

Star Compass

Star Compass enters the battlefield tapped.
{T}: Add one mana of any color that a basic land you control could produce.

Rising Waters

Lands don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player untaps a land they control.

Tidal Force

At the beginning of each upkeep, you may tap or untap target permanent.

Reef Worm

When Reef Worm dies, create a 3/3 blue Fish creature token with "When this creature dies, create a 6/6 blue Whale creature token with 'When this creature dies, create a 9/9 blue Kraken creature token.'"

Desertion

Counter target spell. If an artifact or creature spell is countered this way, put that card onto the battlefield under your control instead of into its owner's graveyard.

Fatespinner

At the beginning of each opponent's upkeep, that player chooses draw step, main phase, or combat phase. The player skips each instance of the chosen step or phase this turn.

Fog Bank

Defender, flying
Prevent all combat damage that would be dealt to and dealt by Fog Bank.

Frozen Aether

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

Capsize

Buyback {3} (You may pay an additional {3} as you cast this spell. If you do, put this card into your hand as it resolves.)
Return target permanent to its owner's hand.

Trinisphere

As long as Trinisphere is untapped, each spell that would cost less than three mana to cast costs three mana to cast. (Additional mana in the cost may be paid with any color of mana or colorless mana. For example, a spell that would cost {1}{B} to cast costs {2}{B} to cast instead.)

Lighthouse Chronologist

Level up {U} ({U}: Put a level counter on this. Level up only as a sorcery.)
LEVEL 4-6
2/4
LEVEL 7+
3/5
At the beginning of each end step, if it's not your turn, take an extra turn after this one.

Darksteel Forge

Artifacts you control have indestructible. (Effects that say "destroy" don't destroy them. Artifact creatures with indestructible can't be destroyed by damage.)

Mana Breach

Whenever a player casts a spell, that player returns a land they control to its owner's hand.

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.

Engulf the Shore

Return to their owners' hands all creatures with toughness less than or equal to the number of Islands you control.

As Foretold

At the beginning of your upkeep, put a time counter on As Foretold.
Once each turn, you may pay {0} rather than pay the mana cost for a spell you cast with mana value X or less, where X is the number of time counters on As Foretold.

Sunder

Chasm Skulker

Whenever you draw a card, put a +1/+1 counter on Chasm Skulker.
When Chasm Skulker dies, create X 1/1 blue Squid creature tokens with islandwalk, where X is the number of +1/+1 counters on Chasm Skulker. (They can't be blocked as long as defending player controls an Island.)

Ward of Bones

Each opponent who controls more creatures than you can't cast creature spells. The same is true for artifacts and enchantments.
Each opponent who controls more lands than you can't play lands.

Static Orb

As long as Static Orb is untapped, players can't untap more than two permanents during their untap steps.

Teferi, Mage of Zhalfir

Flash
Creature cards you own that aren't on the battlefield have flash.
Each opponent can cast spells only any time they could cast a sorcery.

Devastation Tide

Return all nonland permanents to their owners' hands.
Miracle {1}{U} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this 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.

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Chronozoa

Flying
Vanishing 3 (This creature enters the battlefield with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When Chronozoa dies, if it had no time counters on it, create two tokens that are copies of it.

Thran Dynamo

Rite of Replication

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Followed Footsteps

Enchant creature
At the beginning of your upkeep, create a token that's a copy of enchanted creature.

Dream Tides

Creatures don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player may choose any number of tapped nongreen creatures they control and pay {2} for each creature chosen this way. If the player does, untap those creatures.

Shimmer

As Shimmer enters the battlefield, choose a land type.
Each land of the chosen type has phasing. (It phases in or out before its controller untaps during each of their untap steps. While it's phased out, it's treated as though it doesn't exist.)

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Colossal Whale

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Colossal Whale attacks, you may exile target creature defending player controls until Colossal Whale leaves the battlefield. (That creature returns under its owner's control.)

Coldsteel Heart

Coldsteel Heart enters the battlefield tapped.
As Coldsteel Heart enters the battlefield, choose a color.
{T}: Add one mana of the chosen color.

Crush of Tentacles

Surge {3}{U}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Return all nonland permanents to their owners' hands. If this spell's surge cost was paid, create an 8/8 blue Octopus creature token.

In the Eye of Chaos

Whenever a player casts an instant spell, counter it unless that player pays {X}, where X is its mana value.

Storage Matrix

As long as Storage Matrix is untapped, each player chooses artifact, creature, or land during their untap step. That player can untap only permanents of the chosen type this step.

Roil Elemental

Flying
Landfall — Whenever a land enters the battlefield under your control, you may gain control of target creature for as long as you control Roil Elemental.

Palinchron

Flying
When Palinchron enters the battlefield, untap up to seven lands.
{2}{U}{U}: Return Palinchron to its owner's hand.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

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.)

Caged Sun

As Caged Sun enters the battlefield, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Guard Gomazoa

Defender, flying
Prevent all combat damage that would be dealt to Guard Gomazoa.

Vedalken Orrery

You may cast spells as though they had flash.

Unwinding Clock

Untap all artifacts you control during each other player's untap step.

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Island

Omniscience

You may cast spells from your hand without paying their mana costs.

Great Whale

When Great Whale enters the battlefield, untap up to seven lands.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Sol Ring

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Jin-Gitaxias, Core Augur

Flash
At the beginning of your end step, draw seven cards.
Each opponent's maximum hand size is reduced by seven.

Scourge of Fleets

When Scourge of Fleets enters the battlefield, return each creature your opponents control with toughness X or less to its owner's hand, where X is the number of Islands you control.

Whelming Wave

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

Mana Web

Whenever a land an opponent controls is tapped for mana, tap all lands that player controls that could produce any type of mana that land could produce.

Quest for Ula's Temple

At the beginning of your upkeep, you may look at the top card of your library. If it's a creature card, you may reveal it and put a quest counter on Quest for Ula's Temple.
At the beginning of each end step, if there are three or more quest counters on Quest for Ula's Temple, you may put a Kraken, Leviathan, Octopus, or Serpent creature card from your hand onto the battlefield.

Braids, Conjurer Adept

At the beginning of each player's upkeep, that player may put an artifact, creature, or land card from their hand onto the battlefield.

Sapphire Medallion

Blue spells you cast cost {1} less to cast.

War Tax

{X}{U}: This turn, creatures can't attack unless their controller pays {X} for each attacking creature they control.

Sword of Feast and Famine

Equipped creature gets +2/+2 and has protection from black and from green.
Whenever equipped creature deals combat damage to a player, that player discards a card and you untap all lands you control.
Equip {2}

Winter Orb

As long as Winter Orb is untapped, players can't untap more than one land during their untap steps.

Breaching Leviathan

When Breaching Leviathan enters the battlefield, if you cast it from your hand, tap all nonblue creatures. Those creatures don't untap during their controllers' next untap steps.

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Deepchannel Mentor

Blue creatures you control can't be blocked.

Mercadian Atlas

At the beginning of your end step, if you didn't play a land this turn, you may draw a card.