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