Sample Focus - The easiest way to find the perfect audio sample
Freesound - The Freesound Project is a collaborative database of Creative Commons licensed sounds.
FindSounds - Audio web search engine
Premiumbeat - Premiumbeat.com provides high quality Royalty Free Music.
Moody sampler - A cloud connected audio sampler, including 1000+ instruments
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.