Here are some ambient sound sites:

• Noisli
• Soundroun
• Unique noise generators
• A soft murmur
• Ambiphone
• Space dreams
• Listen and create
• Tabletop audio
• Dune soundtrack
• Melodice – music for gaming
• Weightless – relaxation

Here are some background sound loops from YouTube:

• Concentration Music
• Lofi Girl
• Babylon 5 sound
• Star Trek: TNG engine sound
• Star Trek: DS9 ambient sound
• Star Wars Death Star sound
• Star Wars Millennium Falcon engines
• Star Wars Star Destroyer sound
• Firefly engine sound
• 2001 Discovery One sound
• Doctor Who TARDIS sound

• https://cobalt.tools/