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