Reviewable - GitHub code review platform.
Phabricator - Phacility - Phabricator
CodeRush - DevExpress CodeRush for Roslyn uses significantly less memory, works faster, and lets you start Visual Studio faster.
Atlassian Crucible - Collaborative peer code review tool.
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.
Gerrit Code Review - OpenSource Git Code Review Tool