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