Flying

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

When Bloodwater Entity enters the battlefield, you may put target instant or sorcery card from your graveyard on top of your library.

Sunburst (This enters the battlefield with a charge counter on it for each color of mana spent to cast it.)

At the beginning of your upkeep, you may gain life equal to the number of charge counters on Clearwater Goblet.

Hexproof (This creature can't be the target of spells or abilities your opponents control.)

, , Sacrifice Darkwater Egg: Add . Draw a card.

: Until end of turn, if you tap a land you control for mana, it produces instead of any other type.

Inspired — Whenever Deepwater Hypnotist becomes untapped, target creature an opponent controls gets -3/-0 until end of turn.

Dismal Backwater enters the battlefield tapped.

When Dismal Backwater enters the battlefield, you gain 1 life.

: Add or .

Target player mills X cards, where X is the number of lands you control.

Return up to two target creatures to their owners' hands.

Cycling (, Discard this card: Draw a card.)

Each outlaw creature card in your graveyard has encore , where X is its mana value. (Exile it and pay its encore cost: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Magosi, the Waterveil enters the battlefield tapped.

: Add .

, : Put an eon counter on Magosi, the Waterveil. Skip your next turn.

, Remove an eon counter from Magosi, the Waterveil and return it to its owner's hand: Take an extra turn after this one.

: Add .

X target creatures gain islandwalk until end of turn. (They can't be blocked as long as defending player controls an Island.)

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

At the beginning of each player's upkeep, that player untaps a land they control.

Sacrifice a Forest: Regenerate Rootwater Alligator.

: Add .

: Add or . Rootwater Depths doesn't untap during your next untap step.

: Rootwater Hunter deals 1 damage to any target.

: Look at the top card of target player's library.

: Rootwater Thief gains flying until end of turn.

Whenever Rootwater Thief deals combat damage to a player, you may pay . If you do, search that player's library for a card and exile it, then the player shuffles.

At the beginning of your precombat main phase, you may draw X cards, where X is the number of Shrines you control. If you do, discard a card.

Destroy all creatures with power 3 or greater. Then create a Food token for each creature you control. (It's an artifact with ", , Sacrifice this artifact: You gain 3 life.")

The Watcher in the Water enters the battlefield tapped with nine stun counters on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Whenever you draw a card during an opponent's turn, create a 1/1 blue Tentacle creature token.

Whenever a Tentacle you control dies, untap up to one target Kraken and put a stun counter on up to one target nonland permanent.

Defender (This creature can't attack.)

: Wall of Water gets +1/+0 until end of turn.

As Water Gun Balloon Game enters the battlefield, each player puts a pop counter on "0."

Whenever a player casts a spell, move that player's pop counter up one.

Whenever a player's pop counter hits "5," that player creates a 5/5 pink Giant Teddy Bear creature token and resets all pop counters to "0."

Whenever Water Weird deals combat damage to a player, put a +1/+1 counter on Water Weird if the top card of your library is a nonland card. Otherwise, you may mill a card.

Water Wurm gets +0/+1 as long as an opponent controls an Island.

Flying

Ward (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays .)

Waterfront District enters the battlefield tapped.

: Add or .

, , Sacrifice Waterfront District: Draw a card.

Enchant creature

When Waterknot enters the battlefield, tap enchanted creature.

Enchanted creature doesn't untap during its controller's untap step.

: Mill a card. (Put the top card of your library into your graveyard.)

Craft with Island (, Exile this artifact, Exile an Island you control or an Island card from your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

Flying

At the beginning of your upkeep, sacrifice Waterspout Djinn unless you return an untapped Island you control to its owner's hand.

Kinship — At the beginning of your upkeep, you may look at the top card of your library. If it shares a creature type with Waterspout Weavers, you may reveal it. If you do, each creature you control gains flying until end of turn.

When Watertrap Weaver enters the battlefield, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Return up to two target creatures to their owners' hands.

(: Add or .)

As Watery Grave enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped.