I don't use Github massively often but sometimes I have decided to upload something that can hopefully help people out a bit. A couple I want to mention are:
https://github.com/lukos/COM.PixelPin.Utilities.SChannel - A project to configure Windows SChannel (for SSL/TLS) using Powershell either from code or from the command-line.
https://github.com/lukos/CspPolicyBuilder - A .Net class that enables you to easily deploy a Content Security Policy to your .Net web site. It's pretty basic really but just makes creating the policy a little less manual than usual.
https://github.com/lukos/SQLDatabaseBackup - A useful utility for backing up SQL Azure databases to blobs and then downloading them locally to keep in cheap storage that you probably have.