authentik is an open-source Identity Provider focused on flexibility and versatility. You can use authentik in an existing environment to add support for new protocols, implement sign-up/recovery/etc. in your application so you don't have to deal with it, and many other things.
Apache Guacamole is a clientless remote desktop gateway. It supports standard protocols like VNC, RDP, and SSH.
Open source password management solutions for individuals, teams, and business organizations.
Self-hosted, Open Source YouTube Alternative
Nextcloud is an open source, self-hosted file share and communication platform. Access and sync your files, contacts, calendars and communicate and collaborate across your devices.
A self-hosted push notification service.
Forgejo is a self-hosted lightweight software forge. Easy to install and low maintenance, it just does the job.