Next 'Hearthstone' Expansion Kobolds & Catacombs To Launch Next Month With New Single-Player Dungeon Run Mode Blizzard unveiled Kobolds & Catacombs, the next 'Hearthstone' expansion, at BlizzCon 2017. The new set will add 135 new cards, new mechanics, and an interesting new single-player mode named Dungeon Run. by Aaron Mamiit