Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.
docNCRYPT - docNCRYPT is a cybersecurity platform which only focuses on its core services in protecting your email directly from the different email service provider and allows you to integrate your business email portal in the online service.
MailClark - The Slack bot for external communications
encryptomatic - encryptomatic is a smart email encryption software which provides tons of tools in encryption protocols for secure communication and business transaction.
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
LuxSci - LuxSci providing HIPAA-compliant email, secure email & web services.