Salesforce Data.com - Data.com provides company profiles and contact information across millions of businesses worldwide.
FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts
FullContact - Put the power of full contact information into your web or mobile apps.
Clearbit Connect - Clearbit Connect is a free extension that surfaces actionable information on the people who email you.
HookFeed - Customer Analytics in One Click.
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.