Get 6 free drum sample packs fom Slate Digital for free (E-mail registration)
Get lots of free samples/patchs for iOS apps or as Wav files from Electronicsounds (Donations possible).
Lot’s of free soundfonts/samples to download from Flame Studios. These are allowed to be used in your productions.
Sounds of woodlands and forests from all around the world, a growing soundmap bringing together aural tones and textures from the world’s woodlands.
The sounds form an open source library, to be used by anyone to listen to and create from.
Soniss are giving away 50GB+ of high-quality sound effects (intended for games but useful for more) from their catalogue. Everything is royalty-free and commercially usable. No attribution is required and you can use them on an unlimited number of projects for the rest of your lifetime.
Get an extremely wide sample collection of the Roland 727 drum machine free from Samples From Mars.