GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.
ReSharper - ReSharper is a productivity tool for visual studio that provides tools and features to help you manage your code.
Phabricator - Phacility - Phabricator
SonarQube - SonarQube, a core component of the Sonar solution, is an open source, self-managed tool that systematically helps developers and organizations deliver Clean Code.
BitBucket - Bitbucket is a free code hosting site for Mercurial and Git. Manage your development with a hosted wiki, issue tracker and source code.
CodeRush - DevExpress CodeRush for Roslyn uses significantly less memory, works faster, and lets you start Visual Studio faster.