Gitscout - A beautiful Github Issues experience for macOS
SlimPlanner - Team scheduling, resource planning, task management
Zokyo - GitHub Chrome Extension to track and manage issues
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
GitHub Reader - A quick way to browse GitHub issues and pull requests.
WorkPatterns - The modern manager's toolkit: 1:1s, feedback, & recognition