Dialog Messenger - handy and feature-rich enterprise multi-device messenger available for server or cloud – Slack-like, but not Slack-limited
Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
Ripcord - A desktop chat client for Discord and Slack
GitZip - Download or create a download link for a GitHub project folder/sub-folder or file.
Ziggs - Smoothly Share Content Between Devices!
GitHub Hovercard - GitHub Hovercard provides neat hovercards for GitHub.