Feng Office - Feng Office is a commercial Open Source web based solution aimed to enhance collaboration and productivity

Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.

LibreOffice - Free office suite, open source, and compatible with .doc, .docx, .xls, .xlsx, .ppt, .pptx files. Updated regularly – download for free. Originally based on OpenOffice.org.

Creativity 365 - Cross-device content creation suite

Redmine - Flexible project management web application

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.