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