Public - Group chats.
Posteo - Web- and IMAP-based email service. 2GB cost 1€/month.
Webgility - Accounting, Bookkeeping and Inventory Automation for Retailers & Brands
Inbox.lv - Inbox.lv Mail
Islands - Slack for College 🌴
Webmail.ca.za - Free email, file storage, sms and more.