Posteo - Web- and IMAP-based email service. 2GB cost 1€/month.
Gmail Mail Merge - Send personalized emails with attachments
Inbox.lv - Inbox.lv Mail
Nova Inbox - Personalize emails in seconds, right from your inbox
CounterMail - Countermail is a web-based email service. It is hosted in Sweden. Its focus is on privacy.
Tropical.io - Connect your CRM and other sources (Mailchimp, Unbounce, GoToWebinar, Uservoice, and more) and we tell you which leads are hot