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