Here is the full list of all 39 Spiritfarer achievements. It takes around 35-40 hours to unlock all of the achievements on Windows.
Activate all the shrines
Find and shelter all sheeps
Light up all Lighthouses
Fully improve Buck's Lair of Wonders
Have your final conversation with Hades
Discover all recipes
Fully improve Elena's Cubicle
Fully improve Stanley's Playroom
Have your second conversation with Hades
Fully improve Bruce and Mickey's Crib
Sign up to Feedorama
Fully improve Astrid's Bungalow
Tell Astrid about Giovanni's night excursions
Complete thirty errands for Francis
Shear sheeps at least 50 times
Fully improve Atul's Workshop
Complete twelve errands for Francis
Endure 10 of Albert's jokes
Fully improve Alice's Cottage
Have your first conversation with Hades
Make 5 spirits reach the ecstatic mood at least once
Fully improve Summer's Sanctuary
Buy at least 100 items from Raccoon Inc
Sell at least 200 items
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
Complete all collections
Make all spirits reach the ecstatic mood at least once
Build all houses and stations at least once on the boat
Bring all releasable spirits to the Everdoor
Accomplish your very last objective
Fully improve Gustav's Gallery
Use Alex's bus stops 50 times
Collect all figureheads
Unsubscribe from Feedorama
Give a dating advice
Do not tell Astrid about Giovanni's night excursions