This will be the third set of the year, and last as part of the Year of the Dragon. Hearthstone has a standard rotation, meaning that cards from older sets will get rotated out of standard game modes after awhile. The next rotation will come when the first expansion of 2020 launches.
The Year of the Dragon has been one of experimentation for Blizzard, as each expansion has been part of an interconnected story. Rise of Shadows was about a group of villains stealing the floating city of Dalaran, and Saviors of Ulduum focused on the League of Explorers taking the bad guys on. This expansion will bring the story to a close.
Also, the Year of the Dragon finally has an expansion about dragons. Yay!
The set includes Galakrong the dragon, a new Hero card. Invoke is a new Keyword. Invoke can power up certain cards, including Galakrong. Ysera is also returning as a new Legendary card for Druid. Every class is getting its own Legendary dragon.
Hearthstone had a dramatic October. The company faced scrutiny from players, advertisers, and even U.S. senators when it punished Hong Kong player Ng Wai “Blitzchung” Chung after he showed support for the protests in his country after he won a tournament event.