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