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