Email Service Providers (ESPs): ESPs like Mailchimp, HubSpot, and SendGrid offer features for segmentation, automation, and analytics. CRM Systems: Integration with CRM systems like Salesforce can help with better segmentation and personalization. Analytics Tools: Tools like Google Analytics can track user behavior and conversions from your email campaigns. Deliverability Tools: Tools like Return Path and Litmus can help monitor and improve your email deliverability rates.