Refined GitHub - Browser extension that makes GitHub cleaner & more powerful

Video Thumbnails Maker - Allows you to make thumbnails (caps, previews, screen-lists) and screenshots of video files.

Enhanced GitHub - :rocket: Chrome extension to display size of each file, download link and copy file contents directly to clipboard - softvar/enhanced-github

GitZip - Download or create a download link for a GitHub project folder/sub-folder or file.

GitHub Hovercard - GitHub Hovercard provides neat hovercards for GitHub.

GitHub Folder Downloader - Download a single folder of a repository without cloning or downloading the whole repository.