Here is the full list of all 26 Unravel achievements worth 1,000 gamerscore. It takes around 12-15 hours to unlock all of the achievements on Xbox One.
Found a broken half piece
Found the secret in the engine room
Cleared the snow away from all the branches in one go
Found the eighth missing piece
Found the seventh missing piece
Retrieved the stolen piece
Found the collectible in the crushing, zapping death machine
Found the sixth missing piece
Smashed the coal bucket with the excavator to find the hidden collectible
Found the fifth missing piece
Made it to the water wheel without using a log raft
Found the fourth missing piece
Found the secret in the maze section
Found the third missing piece
Found the second missing piece
Removed all thistles in one go
Found the first missing piece
Collect all Achievements
Mend a broken bond
Find every secret
Finish each level from start to finish without dying
Find the other broken half piece
Find the secret hidden in the tree tops where you fly
Make it through the mire in one go without swatting any mosquitoes
Break all the ice on the way to the letterbox in one go
Use your lasso to jump between 25 different points without touching the ground