Aalllllllllllllright, about that Babylonian myth?
Look for Tiamat.
Not the five-headed dragon goddess of evil from D&D, but the mythical Babylonian dragoness. She was, in part, an embodiment of the wild and deadly sea. The story of Marduk slaying her is the story of civilization dominating a dangerous nature, but there's no reason that has to be the case with your goddess. Perhaps they haven't come to a head yet?
Also, look for the Flood of Gilgamesh. If you're leaning in a slightly more CN route, Inana might be a way to go. She was still a total wench, but she had benificent aspects as well. She wasn't *just* untamed nature, at least.
Mythographically, Babylonian sea goddesses came from a patriarchal society, who enjoyed civilization and control, and felt that the wilderness and nature were in the hands of the women and, unless properly dominated, would poison and overwhelm good, decent menfolk and the ladies who cooperated into society.
The reason was a duality; it was moon vs. sun. The sun presided over the day, the crops, giving bounty, giving heat. The moon was darkness, fear, wilderness. It was ever-changing chaos, and it also had a special link to both the ocean and women. In the ocean, the moon governed tides that flowed in and out at it's command. In women, the moon governed the monthly-ish menstraul cycle.
So wherever you get a sea goddess there, you get them set against civilization, just as the random and wild moon is set against the steady and constant sun. Tiamat, feminine, venomous, wrathful dragon, was an embodiment of all the ocean and storm (particularly the hurricane, which came from the sea) was. It was dangerous, it destroyed people, it caused floods. Perhaps also important; it was
Salt Water, which is poisonous and gives no aid to those who use it. Indeed, if the ocean floods in, the fields are destroyed, and civilzation istelf is put at risk, due to it's chaotic, lunar wrath. Inana is really something of a "domesticated" sea goddess, whose role is still chaotic and capricious, changing as the moon and the tides, but who also is capable of great beauty, jus' like the ladies.....
In the frame of a D&D goddess, her alignment would depend on how violently "anti-establishment" she is. If she actively persues the destruction of the homes and cities, caring not for the cries of lament that her violent outbursts cause, she's CE. If she just wants to protect the wilderness, to have an area of freedom, to stop the sun from invading the night, she's CN.
Monster-wise, I'd seek out aquatic humanoids, especially if she's a bit evil, to work your wickedness on the shore. If you can add weresharks or werecrocodiles, that'd be great, since lycanthropy is another affliction of the moon. Sea-based fey would be fun to use, since they're chaos of nature and chaos of the ocean all in one (army of kelpies!). The Kraken is probably one of the greatest allies, if she's evil, because they can control the weather, too. I wouldn't try to preach in cities, but barbarian tribes on the shore may pay tribute to avoid being destroyed by a sudden hurricane.
Remember, you are poison and wrath. You are destroyer and chaos. Water you cannot drink. Hurricanes. Floods. The moon, the night, the wilderness. These are your allies, these are your weapons, these are your goddess.
Take that for what it's worth.
