Here is the full list of all 39 Spiritfarer achievements. It takes around 35-40 hours to unlock all of the achievements on Windows.
Do not tell Astrid about Giovanni's night excursions
Accomplish your very last objective
Build all houses and stations at least once on the boat
Give a dating advice
Find and shelter all sheeps
Complete all collections
Discover all recipes
Endure 10 of Albert's jokes
Use Alex's bus stops 50 times
Activate all the shrines
Fully improve Buck's Lair of Wonders
Unsubscribe from Feedorama
Fully improve Alice's Cottage
Fully improve Astrid's Bungalow
Complete thirty errands for Francis
Bring all releasable spirits to the Everdoor
Collect all figureheads
Light up all Lighthouses
Make all spirits reach the ecstatic mood at least once
Fully improve Elena's Cubicle
Have your final conversation with Hades
Fully improve Gustav's Gallery
Buy at least 100 items from Raccoon Inc
Fully improve Bruce and Mickey's Crib
Fully improve Atul's Workshop
Sign up to Feedorama
Have your second conversation with Hades
Fully improve Stanley's Playroom
Shear sheeps at least 50 times
Tell Astrid about Giovanni's night excursions
Sell at least 200 items
Complete twelve errands for Francis
Fully improve Summer's Sanctuary
Make 5 spirits reach the ecstatic mood at least once
Have your first conversation with Hades
Fully improve Gwen's Lodge
Complete one errand for Francis
Give Furogawa Tour's guide a tip
Make one spirit reach the ecstatic mood at least once