The Bus factor is the number of key developers who would need to be incapacitated to make a package unable to proceed.
This page shows packages that are depended upon by many other packages but have only ever had a handful of contributors commit to the project.
You can help out by reviewing the code for these packages, helping out with open issues and pull requests and lending the maintainers a helping hand if required.
This is an experiment based on contributions and available dependency data from package manager repositories that make it easily available.