The sounds in the Soundly Pro and Soundly Free libraries are cleared for commercial use. Any projects created while subscribing to Soundly Pro stay cleared even if you end your subscription. This includes, but is not limited to: podcasts, films, video games.
The sounds must be used as part of a project with other media. That means that you can not resell the sounds, either as is, or modified.
If you add the Freesounds library, be sure to choose CC0-only in order to only see the sounds which are available for commercial use and do not require attribution. If you have already added the library, you can choose CC0-only by right-clicking on the Freesounds library in the sounds panel within Soundly
All the other add-on libraries are cleared for commercial use.