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 forgotten fragments.
Collect all of the Relic Dust.
Destroy a Forged enemy with a controlled Scorcher.
Find a low-hanging path to the town pub.
Destroy a Forged enemy with an aerial attack.
Annoy Quill by delaying the adventure.
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.
Collect a large amount of Relic Dust.
Enter the Abandoned City alongside Quill.
Enter the Namelhook Mining cave alongside Quill.
Take control over many Forged enemies.
Use your power as a Reader to break many objects.
Unlock the path to the Mire Temple's altar room.
Collect a small amount of Relic Dust.
Light the torches of the Knights of the Sun.
Guide Quill to destroy multiple thorn patches.
Give Quill a high five.
Use a Screecher to unlock the path forward.
Enter the Mire Temple alongside Quill.
Startle Quill from behind.
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.
Use Quill's sword to cut down a lot of grass.