Alan Wake 2

This is a collectibles based achievement for grabbing the 6 Campaign Slogans, and then visiting the watery hall/cafe to pet the mayor. The earliest this can be done is during Saga's chapter named Old Gods, and must be done before the point of no return at the end of the game. You can keep track of your slogan progress inside of Saga's Mind Place, using a board on the wall.
The locations are as follows:
Bright Falls: On one of the roads touching the lodge where you start in this area
Bright Falls: Across the street from the diner
Bright Falls: Near the Wellness Center which is revealed as you make Saga story progress
Watery: Across the street from where your car arrives
Watery: Near the well in Coffee World
Watery: In front of the gate to the trailer park

Once all 6 are found, head to the Watery Hall/Cafe, up to the stage, and find a dog there. Pet them. They will also give you a charm that allows all collectibles (stashes, lunchboxes, nursery rhymes, etc) to be shown on your map when near them.

Alternatively, the dog will show up without the slogans in open free roam before the point of no return.

For this one you must find 6 Mayor Setter Placards in Alan Wake 2.
You can get the last one in Chapter 5 of The Return and once you get back from Valhalla Nursing Home don't go to the Police Station but get to your car and drive to Watery.
There you will find Mayor Setter in a bar.
He will reward you with Mayor Setter Charm which is great for finding missing collectibles.

Here's the video

I got this towards the end of the game, before the point of no return for Saga. The game explicitly tells you when the point of no return is and forces you to save. At that point I had all the relics, except for the one that Mayor Setter gives you. Fast travel to Watery (if you need to see where your car is in Bright Falls hold the button) and go across the street to Suomi Hall. Mayor Setter is on the stage in the first room.

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I don't know if there are conditions for him to spawn, so I will update the solution as I hear from other people

I got this towards the end of the game, before the point of no return for Saga. The game explicitly tells you when the point of no return is and forces you to save. At that point I had all the relics, except for the one that Mayor Setter gives you. Fast travel to Watery (if you need to see where your car is in Bright Falls hold the button) and go across the street to Suomi Hall. Mayor Setter is on the stage in the first room.

.

I don't know if there are conditions for him to spawn, so I will update the solution as I hear from other people