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
Fully improve Elena's Cubicle
Bring all releasable spirits to the Everdoor
Unsubscribe from Feedorama
Use Alex's bus stops 50 times
Collect all figureheads
Make all spirits reach the ecstatic mood at least once
Fully improve Buck's Lair of Wonders
Activate all the shrines
Light up all Lighthouses
Complete all collections
Build all houses and stations at least once on the boat
Have your final conversation with Hades
Fully improve Gustav's Gallery
Fully improve Bruce and Mickey's Crib
Fully improve Astrid's Bungalow
Discover all recipes
Have your second conversation with Hades
Shear sheeps at least 50 times
Find and shelter all sheeps
Fully improve Atul's Workshop
Fully improve Stanley's Playroom
Tell Astrid about Giovanni's night excursions
Do not tell Astrid about Giovanni's night excursions
Endure 10 of Albert's jokes
Sell at least 200 items
Give a dating advice
Fully improve Alice's Cottage
Sign up to Feedorama
Fully improve Summer's Sanctuary
Complete thirty errands for Francis
Make 5 spirits reach the ecstatic mood at least once
Have your first conversation with Hades
Complete twelve errands for Francis
Buy at least 100 items from Raccoon Inc
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