Here is the full list of all 50 The Lord of the Rings: Adventure Card Game - there are Definitive Edition achievements worth 1,000 gamerscore.
You completed 1 Quest
Use Gandalf 100 times to defeat a Boss
Complete a Quest without attacking an Enemy
Complete 500 Quests without playing an Ally
Complete The King of Carrion Encounter
Complete The Shadows Fall Campaign
Complete 100 Quests with no Heroes defeated
Complete 100 Quests with 1 Hero defeated
Complete 100 Quests with 2 Heroes defeated
Travel 5,000 times
Complete "The Shadow's Reach" and "Shadows of Mirkwood" with 6 different Heroes
Complete 1,000 Quests
Deal 100,000 damage to Enemies
Spend 10,000 Resources
Complete "The Shadow's Reach" with 6 different Heroes
Defeat 5,000 Creatures
Defeat 1,000 Creatures
Complete 10 Quests with Aragorn, Gimli, and Legolas
Complete "The Shadow's Reach" Campaign
Draw 1,000 cards during gameplay (after initial setup)
Draw 50 cards during gameplay (after initial setup)
Travel 1,000 times
Travel 50 times
Defeat all Enemies 100 times before traveling
Leave at least 1 Enemy 100 times when traveling
Make 9 custom decks
Complete 100 Quests without playing an Ally
Complete 10 Quests without playing an Ally
Spend 1,000 Resources
Spend 100 Resources
End 1,000 rounds with at least 1 Resource
End 100 rounds with at least 1 Resource
Use a Power 1,000 times
Use a Power 25 times
Complete 100 Quests in which you play the Gandalf Ally card
Complete 50 Quests with no Heroes defeated
Complete 50 Quests with 1 Hero defeated
Complete 50 Quests with 2 Heroes defeated
Complete 10 Quests with no Heroes defeated
Complete 10 Quests with 1 Hero defeated
Complete 10 Quests with 2 Heroes defeated
Resolve 1,000 Objectives
Resolve 25 Objectives
Deal 10,000 damage to Enemies
Deal 100 damage to Enemies
Defeat 5,000 Spiders
Defeat 1,000 Spiders
Defeat 5,000 Orcs
Defeat 1,000 Orcs
Complete 100 Quests