Email Verifier - Email verifier app lets you verify email.
BizProspex - BizProspex offers CRM data cleaning solutions.
Bulk Email Verifier - Clean up your large mailing lists before you use them. Clean list increases your reputation in MailChimp, AWeber, or Campayn.
RingLead - RingLead offers a complete end-to-end suite of products to clean, protect, and enhance company and contact information.
Email Verification on Google Sheets - An add-on for email verification directly in Google Sheets
DEYDE MyDataQ - MyDataQ DEYDE Data Quality optimizes the costs of the campaign identifying duplicate records and unifying the profiles of the clients.