Sample Focus - The easiest way to find the perfect audio sample
Epidemic Sound - Website with licensed music to use in youtube videos
FindSounds - Audio web search engine
SoundsCrate - SoundsCrate is one of the reliable websites that is designed to provide thousands of sound effects and royalty-free music, making you edit or create your own album.
Mixkit Free Sound Effects - Mixkit Free Sound Effects is a website that is introduced for incredible free sound effects, making you use in your cinematic projects without any hurdle.
Zapsplat - Zapsplat Royalty free music is a website that covers an extensive list of royalty-free music, making you download over 85000 sounds effects in a very format like Mp3, FLAC, M4A, WAV, ACC, and many others.