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