The BBC have made freely available their archive of tens of thousands of sound effects, categorized and searchable. Many lengths, playable onsite and downloadable. Top audio quality.
If you've ever tried to build your own library of sound effects, Foley sounds, background and ambient sounds and noises from a hodge podge of online sources, including stripping audio from YouTube, you'll appreciate how convenient this is.
https://sound-effects.bbcrewind.co.uk/