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