Does the job!
NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
DiscoverOrg - DiscoverOrg is an IT sales intelligence platform providing technology marketers access to data, IT org charts, and real time projects.
Email Verifier - Email verifier app lets you verify email.
Clearbit - Clearbit provides Business Intelligence APIs
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
InsideView - InsideView aggregates and curates all the company and contact data, news and social insights, and professional connections you need to do business better.