Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
Calendly - Say goodbye to phone and email tag for finding the perfect meeting time with Calendly. It's 100% free, super easy to use and you'll love our customer service.
GitZip - Download or create a download link for a GitHub project folder/sub-folder or file.
SavvyCal - A scheduling tool both the sender and the recipient will love.
DownGit - Directly download or create download links to GitHub public folders or files.
Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.