GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.
Hunter - Find all the email addresses related to a domain
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
AnyMailFinder.com - Find anyone's email address
BitBucket - Bitbucket is a free code hosting site for Mercurial and Git. Manage your development with a hosted wiki, issue tracker and source code.
EmailMatcher - Find anyone's email address in a matter of seconds, for free