A keychain is a small, practical accessory designed to hold and organize keys or small decorative items. They come in various materials such as metal, plastic, leather, or resin, often featuring unique designs or personalization. Keychains can also include functional elements like bottle openers, flashlights, or USB drives. Many people use keychains as a form of self-expression, collecting them as souvenirs, or attaching them to bags and wallets for added convenience and style.