Smarty - Smarty provides address validation, autocomplete, geocoding and reverse geocoding services covering addresses in over 240+ countries.
Hunter - Find all the email addresses related to a domain
Loqate - The Standard in Global Address Verification
Mail Dump - Powerful Extensions for email addresses extracting, verifying and finding
Addressy - Addressy is address verification software that captures and verifies addresses on websites.
Snov.io - More leads. More sales. More revenue.