Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.
SpamTitan - Comprehensive Email Protection. 99.99% Spam Detection. Blocks phishing, viruses, malware and other email threats.
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
Sanebox - SaneBox is a cloud-based service that allows users to filter and manage their emails.
MailClark - The Slack bot for external communications
MailCleaner - Cloud & on-premise anti spam software for businesses