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