TestSubject - Test how your email subject line displays on mobile devices.
Gmail Mail Merge - Send personalized emails with attachments
analyze.email - Test the spam-y-ness of your emails
Inbox Grader by Freshworks - Free metrics 📈 for your business and team email ✉️
Rename Email - Easily change the subject of any email, by cloudHQ
Dynamic Campaigns by Sigstr - Share the most relevant content in every email