- Audio (Music / SFX / Voice)
- Customization / outfit / skin
- Edition Upgrade
- Game mode
- Map / level
- NPC / enemy
- Player unit
- Story / mission
- Upgrade (Skill / Boost)
[ more categories ]
Audio (Music / SFX / Voice)
Audio DLC is for added content that doesn't affect the gameplay but change how the game sounds.
Music: DLCs may be something like new songs for players to sing via microphone or to play with a guitar controller. Or, it can be the game soundtrack (not just a soundtrack to listen on it's own, that is not a DLC as it doesn't require a game) which changes the music during gameplay to a new tracks.
SFX: stands for Sound Effects. This can change how some actions sound (for example, user interface sounds or battle sounds or any other sound effects during gameplay).
Voice: DLCs are used to make characters sound different. Either additional or new voice-acting may be added. Adding new languages (voice-acted, not as subtitles) which the game didn't initially supported also falls under this category.
This DLC focuses on audio content exclusively. Adding new map/level, new character, new story content which obviously contains new audio materials doesn't require this genre to be selected, and in fact it shouldn't be.