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