Owler - Owler is a crowdsourced data model allowing users to follow, track, and research companies.
Hunter - Find all the email addresses related to a domain
Whatagraph - Whatagraph is the most visual multi-source marketing reporting platform. Built in collaboration with digital marketing agencies
AnyMailFinder.com - Find anyone's email address
QlikSense - A business discovery platform that delivers self-service business intelligence capabilities
Norbert - Norbert is an online tool that helps you to find anyone’s corporate email address.