Here is the full list of all 23 Wraith: The Oblivion - there are Afterlife achievements.
Complete the main narrative
Complete the game & all side narratives
Find all the collectibles, except the Further Miscellany ones
Complete Chapter 1
Complete Chapter 2
Complete Chapter 3
Complete Chapter 4
Complete Chapter 5
Complete Chapter 6
Complete Chapter 7
Use the flash on a spectre
Throw something at a spectre
Remove all the rot in the Mansion
Get the contents of all voice-locked safes
Hide in a wardrobe
Die and return to the Mansion
Find your father's old camera
Complete Tom's Side Narrative
Complete Meadow's Side Narrative
Complete Alan's Side Narrative
Unlock the Insubstantiality ability
Unlock the Wraithgrasp ability
Find all the Further Miscellany collectibles