Code Completion was my first VS extension, originally developed for Visual Studio 2010 (Wow). Now, with the version 1.0.0.8, it supports Visual Studio 2015.
In the first version, it set region name next the #endregion statement when you are updating its name next #region statement in realtime.
In next versions I have added possibility to set (create) region around selected text. Finally, it is possible to predefined region names in options menu.
You can download it here.
Marazt's blog 