Rummy

Hearts of Stone is the first expansion for the game. There's two expansion packs in total. One is Hearts of Stone, recently released. The other is Blood and Wine, due out early next year. Altogether, they're about 30 hours+ of extra content (10 roughly for Hearts of Stone, 20 for Blood and Wine)

You can get the season pass for 20 quid which means you can download both when they're available. Orrrrrr, there's a special edition physical version of Hearts of Stone, where you get some cards that feature in the Witcher 3. Basically, there's a card game within the game (YO DAWG I HURD U LIEK GAMES SO WE PUT A GAME WITHIN UR GAME SO U CAN GAME WHILST U GAME) and the physical Hearts of Stone expansion includes two of the four card decks.

The main game itself is...looooooooong. Seriously, it'll be worth the extra few quid due to its length. You'll probably last the year off The Witcher 3 and Destiny.