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