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
Bring all releasable spirits to the Everdoor
Fully improve Buck's Lair of Wonders
Complete all collections
Activate all the shrines
Make all spirits reach the ecstatic mood at least once
Build all houses and stations at least once on the boat
Collect all figureheads
Fully improve Astrid's Bungalow
Fully improve Elena's Cubicle
Discover all recipes
Unsubscribe from Feedorama
Give a dating advice
Sell at least 200 items
Complete thirty errands for Francis
Find and shelter all sheeps
Shear sheeps at least 50 times
Light up all Lighthouses
Accomplish your very last objective
Use Alex's bus stops 50 times
Sign up to Feedorama
Have your final conversation with Hades
Fully improve Gustav's Gallery
Fully improve Bruce and Mickey's Crib
Complete twelve errands for Francis
Have your second conversation with Hades
Fully improve Atul's Workshop
Fully improve Stanley's Playroom
Tell Astrid about Giovanni's night excursions
Buy at least 100 items from Raccoon Inc
Make 5 spirits reach the ecstatic mood at least once
Fully improve Alice's Cottage
Fully improve Summer's Sanctuary
Endure 10 of Albert's jokes
Have your first conversation with Hades
Complete one errand for Francis
Fully improve Gwen's Lodge
Give Furogawa Tour's guide a tip
Make one spirit reach the ecstatic mood at least once