Sunken Treasures

From publisher blurb:

Our fifth entry in the 10+ Treasures line features 28 aquatic magic items, including a gun that shoots never-ending blasts of water, suddenly expansive armor (mind the pointy bits), a ring that will keep you alive if you're lost at sea (though you probably won't enjoy the experience), a potion that lets you breathe water (and only water), a cloak made of tentacles, and a legendary submersible (including stats for using it with A Sundered World's more in-depth ship rules).

There's also extensive notes on how we go about creating magic items (which we've included with all of our 10+ Treasures collections).