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