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