Here are some popular tools that can be used for identity verification in email marketing:
1. Clearout: A tool that helps in email verification, ensuring that the email addresses in your list are valid. 2. Mailgun: Provides email verification services and helps in improving email deliverability. 3. Google Authenticator: Used for two-factor authentication to add an extra layer of security. 4. DMARC Analyzer: Helps in domain authentication by monitoring and enforcing DMARC policies.