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