Here is the full list of all 38 Moss achievements.
Rescue Argus without a single death.
Destroy two or more Screecher enemies with a controlled Ticker.
Collect all of the Relic Dust.
Collect all of the forgotten fragments.
Finish the first book of Moss.
Defeat the serpent Sarffog.
Climb to the castle bridge alongside Quill.
Break everything within the town pub that can be broken.
Find a low-hanging path to the town pub.
Collect a large amount of Relic Dust.
Guide Quill to destroy multiple thorn patches.
Enter the Abandoned City alongside Quill.
Enter the Namelhook Mining cave alongside Quill.
Destroy a Forged enemy with a controlled Scorcher.
Unlock the path to the Mire Temple's altar room.
Take control over many Forged enemies.
Light the torches of the Knights of the Sun.
Give Quill a high five.
Collect a small amount of Relic Dust.
Use a Screecher to unlock the path forward.
Destroy a Forged enemy with an aerial attack.
Enter the Mire Temple alongside Quill.
Defeat the Screechers first encountered in the Mire.
Use your power as a Reader to heal Quill for the first time.
Follow the Starthing and Quill into the impassable Mire.
Use your power as a Reader to break many objects.
Use Quill's sword to cut down a lot of grass.
Annoy Quill by delaying the adventure.
Startle Quill from behind.
Enter the Clearing alongside Quill.
Discover your first Forgotten Piece.