Content pack

Expansion packs (EP) are a kind of add-ons for games. They make the original game all the more interesting as it provides many new things to the game and are often centered around a theme. They require the original game (also known as base game) to work. Sometimes, collections of the base game and one or more expansion(s) are released called collections or compilations. The Sims 2 also offered mini-expansions called stuff packs (SP), which offered only new objects. Gamers are advised to check what every edition includes before buying it.

Themes
Between The Sims 1, 2, and 3, there have been 15 expansion packs released total (not including Stuff Packs) - between those packs, some themes have been used more than once, some have only been used once, and some have been incorporated into the base game. Some major themes are:
 * Pets: Pets are introduced in The Sims: Unleashed and reintroduced in The Sims 2: Pets. Pets were left out of The Sims 3 base game, so a third pet-related expansion is likely as they are very popular with many fans.
 * Dating: Dating was added with The Sims: Hot Date and reintroduced with The Sims 2: Nightlife. Dating is included in The Sims 3, though it is simplified from The Sims and The Sims 2.
 * Gardening: Gardening was added in The Sims: Unleashed and brought back in The Sims 2: Seasons. Planting seeds and other gardening activities are included in The Sims 3.
 * Vacations: Vacationing was added with The Sims: Vacation, then again with The Sims 2: Bon Voyage, and a similar "travel and adventure-type" theme is planned with The Sims 3: World Adventures, the first expansion pack for The Sims 3 .
 * Magic: Magic was the centerpiece of the final The Sims expansion pack; The Sims: Makin' Magic as well as the final planned The Sims 2 expansion, The Sims 2: Apartment Life. Magic was left out of The Sims 3 base game.
 * Cars: Personal car ownership was introduced in The Sims 2: Nightlife and was incorporated into The Sims 3 base game.
 * Fame: Being famous was the main theme of The Sims: Superstar; fame was not incorporated into The Sims 2 series at all, but a charisma challenge in The Sims 3 allows fame similar to that found in Superstar.
 * College Life: Central theme of The Sims 2: University but was left out of The Sims 3.
 * Weather: Main theme of The Sims 2: Seasons but was left out of The Sims 3.
 * Businesses: The idea of Sims managing their own businesses was central to The Sims 2: Open for Business, and was included in The Sims 3, though business ownership was simplified and businesses could not be founded independently or formed on private lots.
 * Apartments: Created in The Sims 2: Apartment Life, but left out of The Sims 3.
 * Parties: Parties, while always possible to some extent, were the main theme of The Sims: House Party and were automatically included in The Sims 2 and The Sims 3 base games.