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.
Coverity Scan - Find and fix defects in your Java, C/C++ or C# open source project for free
PyCharm - Python & Django IDE with intelligent code completion, on-the-fly error checking, quick-fixes, and much more...
Embold.io - Peer Code Review
ReSharper - ReSharper is a productivity tool for visual studio that provides tools and features to help you manage your code.
Klocwork - Klocwork is a static code analysis and SAST tool for C, C++, C#, Java, and JavaScript.