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