CloudMagic for Mac VS Net-C

Nylas Mail - The Nylas Cloud API powers your application with email, calendar & contacts features. Built-in features for better email, calendar, and contact management.

Inout Webmail - Inout Webmail script is loaded with state of the art features and it allows all mail operations under the same page.

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

Posteo - Web- and IMAP-based email service. 2GB cost 1€/month.

Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.

Zoho Mail - Zoho Mail is a secure, encrypted, and enterprise-ready email solution, a suite of apps tailor-made for your organization's needs.