Overlays are visual elements that sit on top of a base image or video, enhancing the overall design without obscuring the main content. They are commonly used in streams, videos, and digital content to add additional information or stylistic flair, such as frames, text, graphics, or animations. Overlays can be customized to fit a specific theme or aesthetic, often incorporating transparent areas so they seamlessly blend into the background, enriching the viewer's experience by providing useful details or a polished, professional look.