Downloadable content
From VNDev Wiki
Downloadable content, or DLC, is any game-related content (not a patch) that can be downloaded by the player after the purchase of the original game. Usually, it’s used to refer to paid content, with unpaid being marketed as “free DLC”. Common forms of DLC content for visual novels include: soundtrack, digital artbook, or extra stories/routes (typically an offering of fandiscs in Japan, but in the West, fandiscs are currently uncommon).