Hunter - Find all the email addresses related to a domain
Mailwasher - Over 8 million people use MailWasher as their spam filter
Snov.io - More leads. More sales. More revenue.
SPAMfighter - SPAMfighter and Microsoft have built the strongest and most effective anti spam filter for Outlook, Windows Live Mail, Outlook Express & Thunderbird
MailDump Verifier - Powerful Emails Verifying Tool that helps verify email address or validate email addresses
Spam Reader - Spam Reader is a free anti-spam add-on for Microsoft Outlook.