Flash
Ward {3}
You may reveal the second card you draw each turn as you draw it. When you do, you may cast it without paying its mana cost. If you didn't cast a spell this way, create two Treasure tokens.

Callaphe can't be blocked by creatures with mana value 4 or greater.
Whenever Callaphe the Mariner deals combat damage to a player, you get an experience counter. Then if you have three or more experience counters, bless target player.

Enchant player
Enchanted player may cast blue spells with mana value less than or equal to their devotion to blue without paying their mana costs.

Flying
When Charming Siren leaves the battlefield, if it wasn't blocking, you may bless target creature.

Enchant creature
When Left to the Sea enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Hexproof
When Dakran Shipcrusher enters, you may bless target creature.

Enchant creature
Enchanted creature gets -4/-0 and loses flying.

Counter target spell.
Draw a card if you control a legendary permanent.

Scry 1, then draw a card. If you control a Kraken, Leviathan, Octopus, or Serpent, instead scry 3, then draw a card.

Favored
Whenever your Champion attacks, it can't be blocked this turn.

Target player mills two cards, then mills two more cards for each card named Fathomless Dominion in your graveyard.

Whenever you cast a noncreature spell, choose one —
• Create a 1/1 white Human creature token.
• Target player mills three cards.
• Scry 2.

Flying
Haubay's Familiar can block only creatures with flying.
Whenever you draw your second card each turn, put a +1/+1 counter on Haubay's Familiar.

Ward {3}
Whenever Horror of the Mystic Sea attacks, defending player mills two cards. If they milled two nonland cards this way, Horror of the Mystic Sea can't be blocked this turn.

Kraken, Leviathan, Octopus, and Serpent spells you cast cost {X} less to cast, where X is your devotion to blue.

Create X blue Shrine enchantment tokens named Unmarked Shrine with “At the beginning of your upkeep, each opponent mills a card.”
{1}{U}, Exile Lost to Memory from your graveyard: Draw two cards. Activate only if an opponent has eight or more cards in their graveyard.

Create two 1/1 blue Wizard creature tokens with prowess.

Whenever you draw your second card each turn, scry 1 then put a +1/+1 counter on Melancholic Oracle.

Flying
{5}: Draw a card. Activate only if your devotion to blue is three or greater.

Return target creature or enchantment to its owner's hand. If that permanent's controller has eight or more cards in their graveyard, its owner puts it on the top or bottom of their library instead.

Tap up to two target creatures. Put a stun counter on each of them.

Whenever an enchantment you control enters, each opponent mills two cards.

Flash
When Omen of Deception enters, counter target spell unless its controller pays {2}.
{2}{U}, Sacrifice Omen of Deception: Scry 2.

Vigilance
Whenever you attack, bless target creature.