Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
Deck - A multi-timeline viewer for GitHub repository events
GitZip - Download or create a download link for a GitHub project folder/sub-folder or file.
GitKraken Timelines - Communicate major project milestones and deadlines for free
Zube - Project management for developers.
ChronoFlo Timeline Maker - Create beautiful interactive timelines that you can share online