Here is the full list of all 12 Fe achievements worth 1,000 gamerscore. It takes around 12-15 hours to unlock all of the achievements on Xbox One.
Find 12 Silent Helmets
Free an old friend
Jump from one owl's back to another
Gather 10 or more lizards for a conversation
Glide from the top of the waterfall all the way to the marsh
Complete the game
Find all the Fe playing hide & seek
Jump between 10 different trees without touching the ground
Find your first Silent helmet
Learn to climb trees
Unlock all abilities
Lead a bear to a Silent camp