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