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