Kinto : Kinto is a lightweight JSON storage service with synchronisation and sharing abilities.
Garage : An open-source distributed storage service you can self-host to fullfill many needs.
CryptPad : CryptPad is the Zero Knowledge realtime collaborative editor.
Encryption carried out in your web browser protects the data from the server, the cloud ...
cal.com : Open source meeting scheduling tool. Send a link, let others book a slot. Calendly alternative.
GitPrep : GitPrep is Github clone. you can install portable github system into unix/linux. You can create users and repositories without limitation.
droppy is a self-hosted file storage server with a web interface and capabilites to edit files and view media directly in the browser. It is particularly well-suited to be run on low-end hardware like the Raspberry Pi.