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