Email Verifier - Email verifier app lets you verify email.
Lotame - Make your data actionable, learn about your most valuable customers, improve ROI by targeting the right audience and increase relevance across screens.
Bulk Email Verifier - Clean up your large mailing lists before you use them. Clean list increases your reputation in MailChimp, AWeber, or Campayn.
Adobe Audience Manager - Adobe Audience Manager is a data management platform that integrates online and offline data to deliver a unified view of all your audiences
Email Verification on Google Sheets - An add-on for email verification directly in Google Sheets
V12 Data - V12 Data offers rich data sets with verified addresses and emails for personalized marketing campaigns.