#1 Free OneDrive Client for Linux
Realtime application framework (Node.JS server)
Sync Outlook contacts and calendars with Google
Microsoft Integration, Azure, Power Platform, Office 365 and much more
The world's leading open source portal
An open source search engine with RESTFul API and crawlers
Open Source Enterprise Content Management ECM
Generate your own printable graphing paper
Small, powerful, full featured WYSIWYG editor
An easy-to-use open source java-based CMS
Microsoft Exchange compatible server and client libraries
although fully functional, this is a pre-framework that you can extend