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