An expansion is additional software (usually made available for retail sale) that adds new content and features to a game.
The content of an expansion is usually not available to anyone who does not own the expansion, however World of Warcraft has broken this pattern partially by allowing all players to experience some previously exclusive expansion content (professions are the biggest example). Most expansions will not install or run as stand-alone products.
It was stated on an interview before the first World of Warcraft expansion (possibly by Rob Pardo) that "We have made concepts for this expansion, and we already have enough ideas for 5-6 more".
Blizzard has stated it planned to release one expansion per year for World of Warcraft. Yet development of new expansions has taken significantly longer.
WoWWiki has an article for fan ideas about future expansions.
- Warcraft: Orcs & Humans expansions
- Warcraft II: Tides of Darkness expansions
- Warcraft II: Beyond the Dark Portal (first expansion)
- Warcraft III: Reign of Chaos expansions
- Warcraft III: The Frozen Throne (first expansion)
- World of Warcraft expansions
- World of Warcraft: The Burning Crusade (first expansion)
- World of Warcraft: Wrath of the Lich King (second expansion)
- World of Warcraft: Cataclysm (third expansion)
- World of Warcraft: Mists of Pandaria (fourth expansion)
- World of Warcraft: Warlords of Draenor (fifth expansion)
- World of Warcraft: Legion (sixth expansion)
- Hearthstone adventure: Curse of NaxxramasHsW
- Hearthstone expansion: Goblins vs GnomesHsW
- Hearthstone adventure: Blackrock MountainHsW
- Hearthstone expansion: The Grand TournamentHsW
- Hearthstone adventure: The League of ExplorersHsW
- Hearthstone expansion: Whispers of the Old GodsHsW
- Heroes of the Storm expansions
- Expansion 1 (NYI)