I came across this excellent post made by Metemi on the FLipside FL Studio forum. He (or she?) collected an awesome amount of links (70+) to websites that offer free samples, loops, sounds and beats.
The listed sites cover a multitude of electronic music genres. Qubenzis.com is included on this list. All these sites offer legal free downloads of sounds that can be used freely for production of electronic and other music. Some of the sites, like this one, require free registration or email address.
Here below are a few of the links (!). For the complete list I suggest you visit (and bookmark) Free Samples and Loops – HUGE Links List on the FLipside FL Studio Forum. Supposedly Metemi will keep the list updated.
http://www.sounds.beachware.com/ (5000 free sound FX)
http://soundtransit.nl/search/sounds.php (Huge database of Field Recordings)
http://www.hardsamples.com/free-samples-c-40.html?osCsid=49a59bfcc11cae167be7727ff1928d34 (Hard Style)
http://www.nanorecords.co.uk/media/ (Free Psytrance kits, near bottom of page)
https://qubenzis.com/downloads/ (Psytrance) (Reg. Req.)
http://www.hollowsun.com/downloads/index.html (Vintage + other great stuff)
http://tinpan.fortunecity.com/aphex/113/ (Mellotron Samples)
http://www.ppg.synth.net/zip/lib_14_march_2001.zip (PPG WAVE, direct d/l link)
http://samples.kb6.de/downloads.php Vintage Drum Machine Samples
http://www.soundcentral.com/ (Vintage + much more)
http://www.wohmart.com/a6/audio/ (Alesis Andromeda A6 samples)