LinkedIn Sales Navigator for Gmail - Rich contact profiles inside Gmail
HeadReach - The fastest way to find targeted leads with real emails and social profiles
Clearbit for Salesforce – Lite - Rich data on every record in Salesforce for free!
Link2Sheet - Save LinkedIn profiles to a Google Sheet with one click
Clearbit - Clearbit provides Business Intelligence APIs
Sidekick by Hubspot - Customer insight integrated with your email tools.