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