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