Here is the full list of all 16 Newfound Courage achievements.
Clean up the last book the Blank Sending throws.
Make Alex jump off Deadworld too many times.
Make Alex eat sweets till he gets a stomach ache.
Complete the Lorebook.
Complete Newfound Courage.
Fed Jake and Alex some apples.
Complete the entire Return to Otherwhere DLC.
Fight to the death in the Silverpine Arena.