Here is the full list of all 14 Submerged: Hidden Depths achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Finish the Campaign
Collect all Styles
Collect all Diaries
Collect all Flowers
Collect all Creatures
View a Relic at the Home Base
Collect all Relics
Collect all Boat Boosts
Use all Lookouts
Visit all Landmarks
Change Body Style
Change Hair Style
Change Boat Style
Put a Flower in your hair