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