Peekdata - Peekdata is a Schema-less, Rest based Data API Gateway to get Data from Multiple Data Sources
Hunter - Find all the email addresses related to a domain
Eligible - Payment Infrastructure for Healthcare. Eligible is a software suite that increases yield while decreasing cost to collect.
AnyMailFinder.com - Find anyone's email address
DeviceAtlas - DeviceAtlas offers device detection for mobile and connected devices.
EmailMatcher - Find anyone's email address in a matter of seconds, for free