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