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