Pretzel - Keyboard shortcuts for the app you're currently using
Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
KeyCue - Menu shortcuts are supposed to provide quick access to frequently used menu commands.
GitZip - Download or create a download link for a GitHub project folder/sub-folder or file.
Alfred - Alfred is an award-winning app for macOS which boosts your efficiency with hotkeys, keywords, text expansion and more. Search your Mac and the web, and be more productive with custom actions to control your Mac.
GitHub Hovercard - GitHub Hovercard provides neat hovercards for GitHub.