This deck is built around the Submerge / Flooded strategy. It runs almost entirely (W) minions with the Submerge keyword, supported by spells that focus on flooding sites, drowning threats, and drawing cards. I intentionally avoid Spellcaster minions and spells that must be cast through them or through Avatars.

The list follows the new recommended deck size: 60 cards in the spellbook and 30 cards in the atlas.

I originally played with [[Waveshaper]], but recently switched to [[Seer]] because I rarely used [[Waveshaper’s]] ability, and [[Seer]] offers far better card selection and advantage.

Strengths

[[Seer]] plus Rivers (sites) and draw spells lets you repeatedly check and reorder the top of your spellbook or placing cards at the bottom giving great insight in how to play future turns/combos.
[[Drown]], Submerge, and movement abilities give excellent ways to manage the board. [[Coy Nixie]] [[Abaddon Succubus]] [[Unland Angler]] [[Swap]] etc...
Submerged minions are naturally protected from most spells and attacks, making your board harder to remove.

Weaknesses

The deck’s average mana cost is higher than most lists, so losing sites hurts your ability to deploy minions efficiently.
Low-cost minion or token strategies can pressure you early. Fortunately, the deck’s superior control often allows you to recover. (Don't worry about losing too much life early on)

Opening hands generally don’t matter much (99% of the time) for this deck.

I typically only mulligan when facing decks that rely on Water-threshold sites.

Any site that produces (W) counts as a body of water, meaning you can Submerge there. This significantly improves your movement and control options.

Against these decks, I will often mulligan away:

[[Flood]] [[The Great Drowning of Men]]
Sometimes even [[Drown]] if the opponent also uses many Submerge minions.

Notes:

[[Great Old One]] and [[The Flood]] permanently flood the entire Realm, including voids. This gives a massive advantage to your Submerge-based strategy.
Once the Realm is fully flooded, use [[Seer]] to put redundant cards (like extra [[Flood]]) on the bottom of your spellbook so you can draw more relevant threats or answers.

Big Minions:

I am considering removing [[Diluvian Kraken]], as I find myself using it less.
[[Mester Stoor Worm]] has consistently been the better high-impact option and covers a way large area.

Maybeboard Thoughts

The Maybeboard includes a variety of cards I have tested or am considering.

Many are situational, but all of them are strong choices depending on:

your playstyle
your expected matchups
how aggressive or control-oriented you want the deck to feel

This is my First Deck Publish hopefully it makes sense and the annotations are correct

I love to see what other people are playing and think of the game.

The Flood

@Streetshark