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