Github uses a simple, predictable and enumeration-friendly naming convention format for user and organisation accounts:
github.com/$username
Further, this can be very helpful when iterating through users who belong to a specific organisation – simply replace the $company part below with the name of your organisation of interest:
github.com/orgs/$company/people
Contributors to a given public project can be viewed by iterating the $company and $project values in a URL, for example:
github.com/$company/$project/graphs/contributors
Obviously, not all Github accounts are made equal. For searching Github accounts, organisations and repositories based on their star rating, you can use Gitstar Ranking.
Most active users in a specific geographical location can also be found by using Commits Top – it lists the most active GitHub users in different countries.