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