There's already a thread for discussion about the expansion, but rather than having to hijack someone else's thread I'm just gonna compile some information here, feel free to discuss in whichever thread I suppose!
Cards revealed so far-
A picture list of all the cards!
C'thun Specific-
C'thun- 10 Mana, 6/6, Legendary - Battlecry: Deal damage equal to this minion's Attack randomly split among all enemies.
Beckoner of Evil- 2 Mana, 2/3, Common - Battlecry: Give your C'Thun +2/+2 (wherever it is)
Twilight Elder- 3 Mana, 3/4, Common - At the end of your turn, give your C'Thun +1/+1 (Wherever it is).
C'thun's Servant- 4 Mana, 4/2, Common - Divine Shield. Battlecry: Give your C'Thun +2/+2 (wherever he is).
Skeram Cultist- 6 Mana, 7/6, Rare - Battlecry: Give your C'Thun +2/+2 (wherever it is).
Paladin Cards-
Vilefin Inquisitor- 1 Mana, 1/3, Epic - Battlecry: Your Hero Power becomes 'Summon a 1/1 Murloc.'
Stand Against Darkness- 5 Mana Spell, Common - Summon five 1/1 Silver Hand Recruits.
Forbidden Healing- X Mana Spell, Epic - Spend all your Mana. Heal for double the mana you spent.
Steward of Darkshire- 3 Mana, 3/3, Rare - Whenever you summon a 1-Health minion, give it Divine Shield.
Ragnaros, Lightlord - 8 Mana, 8/8, Legendary - At the end of your turn, restore 8 health to a damaged friendly unit.
Hunter Cards-
Giant Sandworm- 8 Mana, 8/8, Epic - If this minion attacks another minion and kills it, it can attack again
Infest- 3 Mana Spell, Rare - Give your minions "Deathrattle: Add a random Beast to your hand."
Call Of The Wild- 8 Mana Spell, Epic - Summon all 3 animal companions.
Princess Huhuran- 5 Mana, 6/5, Legendary - Battlecry: Trigger a friendly minion's Deathrattle effect immediately.
Forlorn Stalker- 3 Mana, 4/2, Rare - Battlecry: Give all minions with Deathrattle in your hand +1/+1.
Druid Cards-
Wisps of the Old Gods - 7 Mana Spell, Epic - Choose One - Summon seven 1/1 Wisps; or Give your minions +2/+2.
Klaxxi Amber-Weaver- 4 Mana, 4/5, Rare - Battlecry: If your C'Thun has at least 10 Attack, gain +5 Health.
Mark of Y'Shaarj- 2 Mana Spell, Common - Give a minion +2/+2. If it's a Beast, draw a card.
Mire Keeper- 4 Mana, 3/3, Rare - Choose one - Summon a 2/2 Slime; or Gain an empty Mana Crystal.
Dark Arakkoa- 6 Mana, 5/7, Common - Taunt. Battlecry: Give your C'Thun +3/+3 (wherever it is).
Warrior Cards-
Ancient Shieldbearer- 7 Mana, 6/6, Rare - Battlecry: If your C'Thun has at least 10 Attack, gain 10 Armor
N'Zoth's First Mate- 1 Mana, 1/1, Common - Battlecry: Equip a 1/3 Rusty Hook.
Tentacles for Arms- 5 Mana, 2/2 Weapon, Epic - Deathrattle: Return this to your hand.
Ravaging Ghoul- 3 Mana, 3/3, Common - Battlecry: Deal 1 damage to all other minions.
Blood Warriors- 3 Mana Spell, Epic - Add a copy of each damaged friendly minion to your hand.
Mage Cards-
Forbidden Flame- X Mana Spell, Epic - Spend all your Mana. Deal that much damage to a minion.
Cabalist's Tome- 5 Mana Spell, Epic - Add 3 random Mage spells to your hand.
Faceless Summoner- 6 Mana, 5/5, Common - Battlecry: Summon a random 3-Cost minion.
Demented Frostcaller- 4 Mana, 2/4, Rare - After you cast a spell, Freeze a random enemy character.
Twilight Flamecaller- 3 Mana, 2/2, Common - Battlecry: Deal 1 damage to all enemy minions
Servant of Yogg-Saron- 5 Mana, 5/4, Rare - Battlecry: Cast a random spell that costs (5) or less (targets chosen randomly).
Priest Cards-
Forbidden Shaping- X Mana Spell, Epic - Spend all your Mana. Summon a random minion that costs that much.
Herald Volazj- 6 Mana, 5/5, Legendary - Battlecry: Summon a 1/1 copy of each of your other minions.
Shadow Word: Horror - 4 Mana Spell, Rare - Destroy all minions with 2 or less attack.
Embrace The Shadow- 2 Mana Spell, Epic - This turn, your healing effects deal damage instead.
Shifting Shade- 4 Mana, 4/3, Rare - Deathrattle: Copy a card from your opponent's deck and add it to your hand.
Warlock Cards-
Possessed Villager - 1 Mana, 1/1, Common - Deathrattle: Summon a 1/1 Shadow Beast.
DOOM!- 10 Mana Spell, Epic - Destroy all minions. Draw a card for each.
Renounce Darkness- 2 Mana Spell, Epic - Replace your Hero Power and Warlock cards with another class's. The cards cost (1) less.
Spreading Madness- 3 Mana Spell, Rare - Deal 9 damage randomly split among ALL characters.
Cho'Gall- 7 Mana, 7/7, Legendary - Battlecry: The next spell you cast this turn costs Health instead of Mana.
Shaman Cards-
Hallazeal the Ascended- 5 Mana, 4/6, Legendary - Whenever your spells deal damage, restore that much Health to your hero.
Thing from Below- 6 Mana, 5/5, Rare - Taunt. Costs (1) less for each Totem you've summoned this game.
Master of Evolution- 4 Mana, 4/5, Rare - Battlecry: Transform a friendly minion into a random one that costs (1) more.
Hammer of Twilight- 5 Mana weapon, 4/2, Epic - Deathrattle: Summon a 4/2 Elemental.
Rogue Cards-
Undercity Huckster- 2 Mana, 2/2, Rare - Deathrattle: Add a random class card to your hand (from your opponent's class).
Xaril, Poisoned Mind- 4 Mana, 3/2, Legendary - Battlecry and Deathrattle: Add a random Toxin card to your hand.
Thistle Tea- 6 Mana Spell, Rare - Draw a card. Add 2 extra copies of it to your hand.
Shadowcaster- 5 Mana, 4/4, Epic - Battlecry: Choose a friendly minion. Add a 1/1 copy to your hand that costs (1).
Neutral Cards-
Validated Doomsayer- 5 Mana, 0/7, Epic - At the start of your turn, set this minion's attack to 7
Corrupted Healbot- 5 Mana, 6/6, Rare - Deathrattle: Restore 8 Health to the enemy hero.
Polluted Hoarder- 4 Mana, 4/2, Common - Deathrattle: Draw a card.
Eater of Secrets- 4 Mana, 2/4, Rare - Battlecry: Destroy all enemy Secrets. Gain +1/+1 for each.
Hogger, Doom of Elwynn- 7 Mana, 7/7, Legendary - Whenever this minion takes damage, summon a 2/2 Gnoll with Taunt.
Infested Tauren- 4 Mana, 2/3, Common - Taunt. Deathrattle: Summon a 2/2 Slime.
Tentacle of N'Zoth- 1 Mana, 1/1, Common - Deathrattle: Deal 1 damage to all minions.
N'Zoth the Corruptor- 10 Mana, 5/7, Legendary - Battlecry: Summon your Deathrattle minions that died this game. (Clarifications on this ruling- The minions N'Zoth summons are random, so if you don't have enough room on your board for all of the summons, expect the unexpected. and N'Zoth will raise silenced Deathrattle minions, but not cards that were buffed with Deathrattle or transformed.)
Y'Shaarj, Rage Unbound - 10 Mana, 10/10, Legendary - At the end of your turn, put a minion from your deck into the battlefield.
The Boogeymonster- 8 Mana, 6/7, Legendary - Whenever this minion attacks and kills another minion, gain +2/+2.
Brood of N'Zoth- 3 Mana, 2/2, Common - Deathrattle: Give your minions +1/+1.
Cult Apothecary - 5 Mana, 4/4, Common - Battlecry: For each enemy minion, restore 2 Health to your hero.
Mukla, Tyrant of the Vale - 6 Mana, 5/5, Legendary - Battlecry: Add 2 Bananas to your hand.
Nightmare Drake - 6 Mana, 2/8, Epic - At the start of your turn, double this minion's attack
Ancient Harbinger - 6 Mana, 4/6, Epic - At the start of your turn, put a 10-Cost minion from your deck into your hand.
Twilight Summoner - 4 Mana, 1/1, Epic - Deathrattle: Summon a 5/5 Faceless Destroyer
Blood of the Ancient One - 9 Mana, 9/9, Epic - If you control two of these at the end of your turn, merge them into 'The Ancient One'. (9 Mana, 30/30, Epic)
Yogg-Saron, Hope's End- 10 Mana, 7/5, Legendary - Battlecry: Cast a random spell for each spell you've cast this game (targets chosen randomly).
Soggoth the Slitherer- 9 Mana, 5/9, Legendary - Taunt: Can't be targeted by spells or Hero Powers.
Deathwing, Dragonlord- 10 Mana, 12/12, Legendary - Deathrattle: Put all Dragons from your hand into the battlefield.
Quick Information drop-
- More Deck Slots on Monday, 3/14
- 134 New Cards Total
- When you login during the promotion period, you'll get 3 Whispers of the Old Gods card packs, and C'Thun.
- Whispers of the Old Gods will be Launching late April, early May.
- A pre-order will be available like TGT and you'll get a C'Thun themed card back, 50 USD, Card backing appearance-
- Arena will not have the C’Thun cards included. Since they have specific synergy with 1 card they decided to not have them even show up in arena at all. (Source, thanks to The Glitch)
- Classic card nerfs will not be announced until much closer to release. They feel it would feel bad to know this far ahead which cards you own will be getting nerfed.
- There will be at least 1 new dragon in this expansion
- No new tribes are added to this expansion.
- C’thun is the only Old God which has the minion support. The other gods will have different style of abilities.
- March 21st will have more information released, wording implies voting system again like past expansions (Vote for X or Y for winner to be shown, "Be sure to visit www.oldgods.com on March 21 to be part of the effort to reveal more about Whispers of the Old Gods.")
- Your friend's list ranking will display your highest rank between Wild and Standard (Ex- If you're rank 10 in Wild Mode, but rank 15 in Standard, your friends will see you as rank 10 on their friend's list) Source
That about sums up the compilation so far. If I missed anything, or there's any suggestions on how to clean this up a bit, feel free to critique!