At the beginning of the lockdown, BBC launched a bunch of newsroom images to add a background on Zoom calls, and more recently, they just opened up access to their searchable bank of thousands of audio clips. While you're free to use the clips for purposes like education, it's a good practice to check the rights for every visual/sound when using it in a project. And if you need music for your video/podcast, you might have better luck at the YouTube Audio Library or Facebook Creator studio. And if you need something more organised, check out audiio.com or Motion Array.
Many video journalists consider the addition of sound effects (like the sound of traffic, or the sound of animals in the background) to be misleading. Because it can influence the audience’s perception of a real-life event or the ambience of a specific location. These ethical concerns might not apply in works such as animated videos, where it’s clear to the audience that the sounds added are not in fact the sounds that the animated characters are making. Other journalists address this potential concern by adding disclaimers, like “representative audio” or “representative visuals”.
While good sound design can really elevate the narrative of a story, it can also colour someone's perception: negatively or positively. That's why some of the earliest documentary makers refused to add any music to their work. If you like geeking out on discussions of ethical dilemmas like these, we recommend reading this piece in CJR about the latest documentaries popping up all over streaming services.