Clearbit - Clearbit provides Business Intelligence APIs
Salesflare - Simply powerful CRM. Automates your data to build better relationships and make more sales.
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.
17hats - The all-in-one business system for entrepreneurs.
InsideView - InsideView aggregates and curates all the company and contact data, news and social insights, and professional connections you need to do business better.
LinkPoint Connect - LinkPoint Connect: Desktop Edition for Salesforce links the work you do in your email to the records you need to update in the CRM.