1. A towering Flower of Glass, free from debris and sea-life. Glittering and beautiful, what secrets does it hold?
2. An upside down Castle Turret, embedded in the bottom like a thrown spear. Remarkably intact given the likely violence of its journey here.
3. A Giant Skeleton, festooned with rusted chains and anchors.
4. An immense Stone Gear, so large that it's nature would not be discovered without mapping it. Otherwise, it seems like a strange stone building.
5. A school of Magpie Octopuses. Thieving little wretches.
6. A Stone Archway, covered in kelp. Perhaps an inactive portal? Remnants of a lost city?
7. What appears to be an Iceberg, sunken to the bottom against all physics.
8. A Small Chest, bound with many chains and padlocks. It contains the live disembodied head of a fell sorcerer. He can cast some magic, but is weakened - much of his energy is spent keeping himself alive. He will say anything to be brought to the surface and be brought into contact with his old followers.
9. Shipwreck! An Ancient Bronze-plated Trireme inhabited by undead sailors who appear as vaguely humanoid figures of billowing ink. Their weapons are still intact spears and gladius-like blades.
10. An Immense Conch Shell, nearly 15' in height. It is filled with air and inside can be found a somewhat batty sea-witch. The air is sustained through the efforts of the witch's tamed octopus followers, who make trips to the surface with airtight baskets to bring fresh air down to her.
11. The Whale's Graveyard - normally, whales simply drift away from where they perish. The whales in this region - of all types from the smallest to the largest, have adopted this area as their final resting place. Whale-bone exists aplenty, and the bottom is also home to very large and aggressive crabs.
12. The Pipe. A massive metal pipe protrudes from the sea floor. A cloud of toxic water issues forth from it. Where does it come from?
13. A Black Cloud. A great mass of a coherent, ink like-substance can be seen moving - even against the current. It is not heading towards the players, but is charging ahead with apparent purpose in another direction.
14. Music from the deep, seeming to originate from waters deep below, the PCs hear surprisingly clear music.
15. A Wonderful Sword, free from rust and barnacles - obviously magical. And of course, it is cursed, tossed here in attempt to free someone from it.
16. The shapes and forms of Dozens of Gravestones on the bottom. No other structures can be found nearby, and the water is quite deep.
17. A standing Whirlpool - looking like a submersed tornado. Within, someone screams for help. Anyone touching the whirlpool will be drawn inside, releasing someone trapped within. If an occupant is rescued without someone replacing them (ropes, etc), the whirlpool dissipates.
18. An Oil Lamp sits in a Massive Open Oyster Shell, lit and burning. Bubbles filled with smoke drift upward rapidly. Two giant moray eels lair nearby, having grown fat from the fish drawn by the light.
19. An immense Statue of a Human, perhaps five stories high. It is covered with coral and at first its nature is not clear.
20. A sandy field of Gems! On close examination, they are nothing more than beach glass.. They could be the lure for some nasty underwater predator, or the bower for an amorous one.
21. Perhaps due to some vast upheaval, a Relic of the Trench Dwellers has been brought up into the shallows.
22. A Necronautalis is chained to a post here. It belly contains a random assortment of undead in its belly it will disgorge if intruders investigate.
23. A huge Stone Boulder, the size of a house, floats above the sea-floor like a displaced planet. It is covered with coral and other creatures, and appears to have been here for quite some time. Is there something inside?
24. A giant Net, incredibly strong, has snagged on rocks on the bottom. It is full of long dead, recently dead and currently struggling sea creatures of all description. Nothing short of powerful magic or superhuman strength can cut the threads, suggesting a powerful divine origin. This is certain to draw marine predators in droves.
25. A Hydra Anemone - a massive anemone with snake-headed tentacles. If severed too far from the head, say 3’ or more, the detached tentacle will fight independently like a sea snake. Of course its bite is venomous.
26. Some anomaly has created a Swarm of Voracious Sea Slugs. There’s got to be dozens of em!
27. A number of Shipwrecks are lined up carefully, almost as if at port. This is a ship collection created by a Black Leviathan who helped sink some of these vessels and would not appreciate intruders.
28. A young girl hosting an Imaginary Tea Party with her stuffed animal friend. Just the sort of tea party you'd expect to see at some point in nearly every young girl's life. Just... you know... not on the bottom of the ocean. She doesn't seem to understand any reference to her current location and thinks you're playing make believe. (submitted by Longspeak)
29. A swarm of Intact Parchment Sheets flowing together like a school of fish, though milling around randomly. The sheets are from a book that was partially protected magically. All pages and the covers are nearby and apart from being unbound, undamaged. Some may be hidden inside shellfish or other hiding places. The book, when completed, is a spellbook with potent spells or perhaps some other magical work.
30. A Petrified Forest - hundreds of tall, leafless tree trunks, surprisingly bare of coral and barnacles. To the careful eye, even individual species can be recognized. At night, ghostly figures can be seen walking through the leafless forest.