Here is the full list of all 17 A Tiny Sticker Tale achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Receive Joy medallion
Receive Love medallion
Receive Safety medallion
Receive Self-confidence medallion
Receive Perseverance medallion
Read the last letter
Take all lost fairies home
Repair water mill
Re-unite the lost brothers
Unlock all stickers in the collection
Watch a rainbow in the sky
Help the witch with her ritual
Brotherhood prays to the light goddess
Brotherhood prays to the dark goddess
Win the archery trophy
Win the Sticker-Tennis trophy
Find Figori Island's hidden treasure