Here is the full list of all 31 Yoku's Island Express achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Complete Thorn quest
Collect every ability upgrade
Try every ball style
Hatch the God Egg
Collect all Wickerlings
Activate all Scarabs
Complete Rinri's quest
Complete Willo's quest
Unlock all treasure chests
Become the Postmaster
Complete the story
Get the biggest wallet
Discover Fosfor’s Lair
Defeat the Spider
Unlock all the Beelines
Befriend a Sootling
Defeat Screetch
Deliver the cake to the inventors house
Customise Yoku’s ball
Complete the temple trials
Discover the heart cluster at the bottom of the sea
Ride the Beeline
Save Spina
Collect the Divefish
Suck up a slug with the Slug Vacuum
Take the surviving egg to Dipperloaf
Toot the noisemaker 1000 times
Find the Post-office
Free Kickback
Toot the noisemaker 100 times
Blow the noisemaker