New darkmoon card will be added, but requires collecting cards, where do you get cards?
Azerothian Guardians drop the Ace
Treasure chests drops 3 different ones.
Several crypt bosses has last 4 ones, the last one has highest chance on hitting the drop pool!
What else... Well Azerothian Guardians (has chance on spawning when opening a chest) drops a mobile tank that you can use for 5 minutes also a portable buffer.
To be mentioned that if a player collects the new deck, it doesn't come that easy... Instead of giving out the card you'll receive 3 Azerothian Tables that grants access to fight upcoming boss that drops BiS Helmets for every spec along with chance on hitting Onyxia/Yogg-Saron/Algalon/General Vezax loot table, so 1 BiS Helmet is guaranteed + Drop table that was mentioned earlier giving total of 2 item drops, also a pet of the boss that is kinda cool, she can morph you and cast buffs.
Note: Each try of the boss takes away one Azerothian Table, so be prepared! (and the new card will be added aswell to the upcoming boss)