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
Nova Inbox - Personalize emails in seconds, right from your inbox
Rename Email - Easily change the subject of any email, by cloudHQ
Tropical.io - Connect your CRM and other sources (Mailchimp, Unbounce, GoToWebinar, Uservoice, and more) and we tell you which leads are hot