The first new Hearthstone set of 2018, The Witchwood, marks the beginning of the New Year of the Raven, the rotation of the three old sets, and the introduction of the whole new meta. Just imagine that Jades are gone, Ice Block and Kazakus are gone, Evolve Shaman is gone, and all the Old Gods are also gone.
This means that the new meta will mostly revolve around all the new mechanics from The Witchwood, such as Echo, Rush, and Odd/Even-cost effects. Classes like Druid and Hunter will rely mostly on beast synergies, while Mage and Shaman will keep utilizing elementals.
If you're an F2P player or a beginner, then be sure to check out all nine freshly crafted decks for The Witchwood meta that cost less than 2,000 dust and have accompanying deck strings, which can be simply copy-pasted into your Hearthstone client.