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