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