We are huge fans of Mode Audio’s sample packs (particularly their Ambient selection) and they are currently offering 800MB of free content if you join their free newsletter.
You get a huge amount of 100% royalty-free music loops, samples and synth presets, MIDI loops and even field recordings after you sign up. These files are taken from the packs:
• Glide: Chill Electronic Loops
• LA Beats
• Neon Dream: Massive Retro Presets
• Fragment: FX Drum Samples
• Spray: Granular Texture Samples