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