Expansion pack

An expansion pack is an addition to an existing game. These add-ons usually add new game areas, weapons, objects, and/or an extended storyline to a complete and already released game.

Sometimes development of an expansion pack is contracted out to third-party company or the developer may choose to develop the expansion itself.

Diablo I

 * Diablo: Unearthed Arsenal
 * Diablo: Hellfire

Diablo II

 * Diablo II: Lord of Destruction
 * Diablo II: Salvation (canceled)

Diablo III

 * Diablo III: Reaper of Souls
 * Diablo III: The King in the North (canceled)