The BBC have apparently released a library of around 16,000 sound recordings in WAV format, free to use under the RemArc license (basically no commercial use, include BBC credit)
Using these sounds in soundsets for personal use only should be fine. Using them in community shared soundsets …might be OK, depending on how you interpret “commercial use”.
But as someone whose personal journey into the world of sound effects started with a scratched old vinyl BBC Sounds Effects LP (“No 16 Disasters”) bought at a car boot sale, I’m excited to see this.