The game features 11 major expansion packs released between 2009 and 2013. Steam Community The Sims 3 Expansion Packs (Release Order)

Adds weather effects, seasonal festivals, and holidays like Spooky Day.

The expansions are essential:

You must manually tell the game to recognize modern graphics cards (RTX 30 series, etc.).

It is almost criminal to play the base game without Seasons. This expansion adds weather, holidays, and seasonal activities. Watching the leaves change color in autumn or having snowball fights in winter adds a layer of immersion that makes the open world feel truly alive.