https://www.gamespot.com/articles/see-all-135-new-hearthstone-witchwood-expansion-ca/1100-6458107/

Today Blizzard revealed the final cards for its upcoming Hearthstone expansion, The Witchwood. This latest addition to the digital card game will add 135 cards in all when it launches this Thursday, April 12. It all centers around a spooky haunted forest theme with creepy new features and keywords.

Rush, one of the new keywords, is similar to the existing Charge mechanic but restricted only to attacking minions on the turn they are first played. The other is Echo, which lets you play the same card multiple times in a turn as long as you have the mana to pay for it. Other mechanics add flavor without their own devoted keyword. Worgen characters swap attack and health (and visual art) every turn they're in your hand. Finally, some of the new cards have special effects if you build a deck only out of even- or odd-costed cards.