Sound effect libraries are collections of audio recordings that provide various sounds for use in media projects, such as films, video games, and podcasts. These libraries contain a wide range of sounds, including nature sounds, human sounds, and mechanical noises, allowing creators to enhance their work with realistic audio. Many sound effect libraries are available online, offering both free and paid options. Users can browse through categories or search for specific sounds to find the perfect audio clip for their project. Popular examples of sound effect libraries include Freesound, SoundSnap, and AudioJungle.