Roundcube - Web-based IMAP email client
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
Horde - Horde Groupware is a free, enterprise ready, browser based collaboration suite.
Creativity 365 - Cross-device content creation suite
Rainloop - RainLoop is a web based email client.
Microsoft Teams - Microsoft Teams provides the enterprise-level security, compliance and management features you expect from Office 365, including broad support for compliance standards, and eDiscovery and legal hold for channels, chats, and files.