Mail Dump - Powerful Extensions for email addresses extracting, verifying and finding
Proofy - Quickly validate and verify your email lists.
Kaspr - Get access to your prospects’ phone numbers and email, instantly.
Breadcrumbs Free Email Verifier - Free forever to validate up to 10,000 emails with 1-click
Castle - The easiest way to protect your users from getting hacked
Email Verification Tool - A Google Sheets add-on for bulk email verification