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