Git Random - Chrome extension to replace new tab with random github user
Mergefly - A modern UI for GitHub pull requests
Code Climate for Google Chrome - Code quality and test coverage, directly in GitHub
PullRequest.com - Code review as a service
Devo - Devo delivers real-time operational & business value from analytics on streaming and historical data to operations.
Codementor - “Instant help from expert developers. Codementor is your instant 1:1 expert mentor helping you in real time.”