SoundBible.com is a browsable library of free sound clips, each individually tagged as either Creative Commons Attribution 3.0 or Public Domain, alongside a separate paid premium section.
Value is quick, simple browsing with only two possible license types per sound, rather than the wider spread of terms on larger CC aggregators.
Fits quick one-off SFX needs where you're willing to check each sound's specific attribution-vs-public-domain tag.
Public Domain sounds need no credit; Attribution 3.0 sounds must be credited to the listed creator before commercial use: check the tag on each individual sound page.
Free sound effects, most cleared for commercial use.
