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