Email Verification on Google Sheets - An add-on for email verification directly in Google Sheets
Phiona.com - Phiona is a data management platform that empowers you and your team to clean, combine, transform and automate your organization's data in minutes.
Verifier - Weed out disposable, non-existent domains or invalid emails.
n8n.io - Free and open fair-code licensed node based Workflow Automation Tool. Easily automate tasks across different services.
Clearbit Salesforce Prospector - Quickly build targeted lead lists directly in Salesforce
SyncWith for Google Sheets - Data from any app into Google Sheets, reports & dashboards