Cookie Clicker

The 2013 Orteil classic that arguably defined modern idle gaming. Click a giant cookie, recruit grandmas, farms, factories, mines, and stranger things to bake cookies for you, ascend for prestige bonuses, and chase hundreds of achievements. Actively developed for over a decade and still playable free in any browser at the official site, with a feature-rich paid Steam version that adds modding, Steam Workshop and cloud saves.