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