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