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