Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.
Loop Email - Emailing for teams: Organize your Inbox into channels 💌
Hiver - Manage Customer Support, Sales and Projects right from your Gmail inbox. Collaborate with Shared Labels, Shared Contacts, email notes, email reminders and email templates
Mailtrim - Email lives forever!. Reinvigorate your emailing experience with the best free email client, the Mailtrim
MailClark - The Slack bot for external communications
FastMail - Email, calendars, and contacts to highest standards of security, privacy and reliability.