Here is the full list of all 16 Cards and Castles achievements.
Unlock all 5 factions.
Win a multiplayer game.
Deal 10 or more damage in a single attack.
Lose a multiplayer game. It's ok, really!
Collect at least one legendary card!
Destroy the enemy castle while the opponent has no units in play.
Craft 10 cards!
Craft one card using shards.
Win 3 or more matches in a single draft.
End a turn with at least 6 buildings in play.
Win 10 multiplayer games.
Disenchant a card!
Collect 5 legendary cards.
Win a game with only 1 health left on your castle.
Deal 1000 total damage from attacks.
Craft 50 cards!