Here is the full list of all 26 Tales from Candlekeep: Tomb of Annihilation achievements.
Craft every item in the game
Complete all Story Quests and Side Quests on Horrific Difficulty
Complete all Story Quests and Side Quests on Hard Difficulty
Craft all of Birdsong's Legendary items
Craft all of Dragonbait's Legendary items
Craft all of Asharra's Legendary items
Craft all of Artus Cimber's Legendary items
Stun the Vegepygmy Chieftain and his 3 Vegepygmy Warriors in a single turn
With a party of 4, never let Kothar Pounce more than once during a Villain Phase
Complete Story Quest "Acererak's Crypt" with only one hero in your party
Complete Story Quest "Acererak's Crypt"
Complete all Story Quests and Side Quests on Normal Difficulty
Complete Story Quest "The Juggernaut"
Destroy the Stone Juggernaut
Complete Story Quest "Misty Passage"
Complete Story Quest "The Unwilling Key"
Complete Story Quest "Ras Nsi"
Complete Story Quest "Watch the Skies"
Complete Story Quest "Heart of Ubtao"
Complete Story Quest "Undead Hunt"
Complete Story Quest "Nanny Pu'pu"
Complete Story Quest "The Great Ape"
Complete Story Quest "Hedge Trimming"
Roll a natural 20 for the first time
Complete Story Quest "Favor for Jessamine"
Craft an item for the first time