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