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