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