One of the new changes coming to Hearthstone in the Witchwood expansion is the Echo. The new keyword has some spooky applications, allowing you to continue to re-use cards as long as you have enough mana.
Hearthstone: Heroes of Warcraft Archives
The next expansion for Blizzard's Warcraft trading card game, Hearthstone, will include the haunted boughs of The Witchwood, which will bring 135 new cards, complete with some spooky new game mechanics. And yes, there will be a witch or two for you to burn in that massive card drop.
Hearthstone is entering its next year, Year of the Raven, which will come with a new Standard format, a new expansion, and a new druid hero Lunara.
Blizzard has gone live with Hearthstone update 10.2 today which brings a few balance changes to the game in addition to some Wild Events in celebration of the Year of the Mammoth.