Hunter - Find all the email addresses related to a domain
AnyMailFinder.com - Find anyone's email address
SignalHire - Valid personal & work emails and phone numbers. Real-time verified contact info for recruiters, sales professionals, and marketeers.
AeroLeads - AeroLeads is a lead generation software which finds prospects with email and phone number.
Lusha - Search less. Sell more.
LeadGibbon - Access millions of business contacts, with verified email addresses and phone numbers