Shadow of Revan

The earliest instances of unmarked Lore items on Manaan began in Shadow of Revan, with four Placards placed around the small hub that housed the Depths of Manaan flashpoint and concourse with Lana and Theron.

Aside from the Codex Placard to discover Ahto City, there are 4 placards you can visit at anytime that delve into the Lore surrounding the Order of Shasa and their control over the City in this area including limiting alcohol consumption and upholding native beliefs while in the area and restrictions imposed upon the Sith Empire.

Placard 1: :: OFFICIAL NOTICE :: The Order of Shasa
Please note that the Mercantile Plaza is intended for trade-related activities only. Travel by offworld visitors to any other location on Manaan may be approved on a case by case basis, though approval is highly unlikely.
Travel to Selkath cities, domiciles or government buildings is strictly prohibited. We also kindly ask that you do not swim or bathe in plaza fountains. Thank you, and welcome to Manaan.

Placard 2: :: OFFICIAL NOTICE :: The Order of Shasa
Effective immediately, the number of beverages that may be bought and consumed in one visit will be strictly limited. This limit will be strictly enforced.
As always, please remain mindful of cultural norms, particularly as regards maintaining a respectful distance and tone with your Selkath hosts. Thank you.

Placard 3: :: OFFICIAL NOTICE :: The Order of Shasa
This transport terminal is presently closed for maintenance. We apologize for any inconvenience.
Terminal Recommencement Date: UNDER CONSIDERATION

Placard 4: :: OFFICIAL NOTICE :: The Order of Shasa
As a courtesy to the citizens of Manaan, please refrain from the following:
-Mass congregations of personnel
-Brandishing weapons
-Interrogating Selkath
-Conspicuous loitering
We also remind you that the presence of an more than two Imperial capital ships in orbit at any one time is strictly forbidden under our current Terms of Trade with the Sith Empire. Thank you.

An important note is that Placard 3 and 4 are relevant to the story that takes place on Manaan during Shadow of Revan. Exiting the flashpoint will spawn you at the bay where Placard 3 is found, inferring that you surfaced the escape submarine into the Transport Terminal.
Placard 4 is relevant as the four actions taken are things that the player does in the Depths of Manaan flashpoint (Congregating a group, attacking Selkath, Interrogating Selkath scientists, loitering).

Legacy of the Sith

The unmarked lore placards are very diverse in Legacy of the Sith and can be found throughout the Invasion Zone, within the Public Arrivals Port and attached underwater section. These have more to do with the day to day life of Selkath before the renewed Sith invasion disrupted life on the planet.

There are four unmarked Lore blurbs above water and 6 below, one of which has a bonus Codex Entry with extra information surrounding an offerworlder who intergrated!
By now references to the Order of Shasa are all but gone, instead there are general laws for the Public and tourism yet remain strict with their dealings of offworlders.

Public Arrivals Port (above water)

Placard 1: Public disturbances are strictly prohibited. Transgressors will be punished to the fullest extent of the law.

Placard 2: Please help keep Manaan clean. Dispose of all waste in the designated receptacles.

Placard 3: Do not leave children unattended. Any unnaccompanied minors will be escorted offworld at our earliest convenience.

4. Kolto Barrels: These Kolto tanks appear to be tampered with, but stable-at least for now. Why would someone intentionally do this?
(Kolto Barrels are a hidden clickable object that progress the Manaan Sightseer achievement)

Visitor’s Center Exploration Dome (under water)

Placard 1: The firaxan shark is the most abundant-and most remarkable-shark species on Manaan. Most firaxan sharks grow to enormous sizes over the course of their incredibly long lifetimes.

Placard 2: Don’t count a binexan shark out! When this feisty fish loses the upper hand in a fight, it only pretends to be defeated. After retreating to the depths, it recuperates and returns, stronger then ever!

Placard 3: “Here we mark the passing of many brave Selkath patriots, who made the ultimate sacrifice protecting the waters of our homeworld, and continue to do so in the face of overwhelming odds. You are forever honored, your memory rests in glory.”
(Placard 3 is a hidden clickable object that progress the Manaan Sightseer achievement)

Placard 4: In honor of Ahto University professor, Doctor Narlan Syphus. Though his home and family were far from our waters, he dedicated his life to the protection and preservation of Manaan’s creatures.
(Placard 4 gives the Codex Entry: Selkath Isolationists: The Syphus Collective when clicked.)

Placard 5: Matawo coral-named for the children of the biologist who discovered this particular subspecies-is a wonder among wonders. Matawo coral grows only in the vicinity of kolto, and during the peak of its two year spawn cycle, will glow just like the blue substance!

Placard 6: Some consider the bakita crab a parasite, but the benefits they provide to the creatures they attach themselves to is undeniable! Without the bakita crab, many species of fish would be overwhelmed by the invasive pest known as water lice.

Much of the Visitor’s Center placards clearly reference aquarium like tourism with flora and fauna both native and invasive to Manaan. However even this zone is not free of Manaan’s extremist militia, and has seen the area overtaken by Selkath Separatists wishing for an isolationist government.

Codex Entry granted by clicking Placard 4:

Sources:
Manaan – SWTOR: Prelude to Shadow of Revan
Flashpoint: Depths of Manaan – SWTOR: Prelude to Shadow of Revan
Manaan Invasion Zone – SWTOR: Legacy of the Sith
Codex Entry: Selkath Isolationists: The Syphus Collective
Achievement: Manaan Sightseer – Manaan Planet