Clearbit Connect - Clearbit Connect is a free extension that surfaces actionable information on the people who email you.
Improver - Improver Chrome extension helps you to find personal email addresses from social networks.
FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts
SignalHire - Valid personal & work emails and phone numbers. Real-time verified contact info for recruiters, sales professionals, and marketeers.
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.
Ampliz Sales Buddy - Data to power your business