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