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
Make all spirits reach the ecstatic mood at least once
Do not tell Astrid about Giovanni's night excursions
Unsubscribe from Feedorama
Activate all the shrines
Bring all releasable spirits to the Everdoor
Complete all collections
Discover all recipes
Collect all figureheads
Light up all Lighthouses
Find and shelter all sheeps
Give a dating advice
Use Alex's bus stops 50 times
Fully improve Buck's Lair of Wonders
Fully improve Elena's Cubicle
Have your final conversation with Hades
Build all houses and stations at least once on the boat
Fully improve Gustav's Gallery
Sign up to Feedorama
Have your second conversation with Hades
Complete thirty errands for Francis
Fully improve Bruce and Mickey's Crib
Endure 10 of Albert's jokes
Fully improve Astrid's Bungalow
Tell Astrid about Giovanni's night excursions
Fully improve Atul's Workshop
Fully improve Stanley's Playroom
Complete twelve errands for Francis
Shear sheeps at least 50 times
Buy at least 100 items from Raccoon Inc
Sell at least 200 items
Fully improve Alice's Cottage
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
Fully improve Gwen's Lodge
Complete one errand for Francis
Make one spirit reach the ecstatic mood at least once