https://www.gamespot.com/articles/hearthstone-all-135-hearthstone-witchwood-expansio/1100-6458107/

Hearthstone's latest expansion, The Witchwood, is now available, and it of course brings new cards to add to your deck. This latest addition to the digital card game brought 135 cards in all, complete with some new twists. 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.