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
Drip Scripts - Create automated email sequences in 60 seconds
Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
DuoCircle - DuoCircle provides enterprise spam filtering and email management solutions.
Polymail Sequences - Simple, powerful multi-stage email campaigns