Here is the full list of all 97 Divinity: Original Sin 2 achievements. It takes around 200 hours to unlock all of the achievements on Windows.
Sebille: Destroy the Mother Tree
Share Divinity with The Doctor
Sebille: Serve the Mother Tree
Beast: Assassinate the Queen
Beast: Ally with the Queen
Ifan: Kill Lucian
Ifan: Forgive Lucian
Learn of the Council of Seven's location from Malady
Lockpick your way into Mordus' hidden lair
Fane: Embrace this strange new world
Fane: Return the Eternals to Rivellon
Craft a grenade
Lohse: Embrace your demon
Kill an enemy using Teleportation
Pray at every altar on the Nameless Isle
Escape Dallis' siege on the Lady Vengeance after killing every minion
Kill Slane
Force Dallis to retreat from combat in Fort Joy
Complete the game in Tactician Mode
Complete the game in Honour Mode
Make a deal with Adramahlihk
Use the Curse skill
Swear to the Covenant
Escort Saheila outside without fighting the Lone Wolves
Take the ferry to Bloodmoon Island
Set Gareth on a path of vengeance
Receive Dorotya's kiss
Escort the Black Cat out of Fort Joy
Escape the kraken's clutches
Successfully begin a Game Master session
Successfully begin a match in Arena Mode
Submit to the God King
Purge Rivellon of all Source
Share Source with all of Rivellon
Complete the game in Explorer Mode
Complete the game in Classic Mode
Ascend to Divinity
Defeated the Kraken
Obtain Anathema
Discover Reimond's Lair
Gain entrance to Lucian's Crypt without following the Path of Blood
Successfully walk the Path of Blood
Persuade Toyseller Sanders to give you his amulet
Rescue Arhu
Gain the Villain tag
The Red Prince: Become the father of dragons
The Red Prince: Kill the Red Princess
Lohse: Banish your demon
Defeat Adramahlihk
Arrive at Arx
Discover the hidden entrance to the Academy
Convince Alexandar to ally with you
Enter the Academy
Enter The Arena of the One
Convince all party members to let you ascend
Sebille: Kill the Master
Arrive at the Nameless Isle
Adopt Peeper
Perform successful surgery on Natalie
Tame Featherfall
Destroy every Voidwoken egg in Reaper's Cove
Awaken the corrupted Ancestor Tree on Bloodmoon Island
Learn of the Council of Seven's location from The Advocate
Learn of the Council of Seven's location from a higher power
Correctly answer all of Crispin's questions
Craft a skill
Serve Garvan the tainted stew
Speak to an animal's spirit
Unlock your third Source Point slot
Unlock your second Source Point slot
Gain the Hero tag
Help free Mari from the Voidwoken
Kill Andras, the necromantic dog
Set Gareth on a path of reconciliation
Meet Meistr Siva
Craft a scroll
Become champion of the Driftwood Arena
Get caught breaking the law
Arrive at Reaper's Coast
Shapeshift into every race
Enter the Hall of Echoes
Escape Dallis' siege on the Lady Vengeance without killing every minion
Take command of the Lady Vengeance
Welcome Tarquin to the Seekers' service
Defeat Alexandar in Fort Joy
Kill Radeka
Face a higher power
Equip runes to all of an item's available slots
Win a persuasion event
Rescue Gareth from Braccus' Armoury
Use your first Source Skill
Arrive at the Sanctuary of Amadia
Flee Fort Joy for good
Remove your Source Collar
Become champion of the Fort Joy arena
Arrive at Reaper's Eye
Perform a successful theft