https://github.com/leiweibau/Pi.Alert
Scan the devices connected to your WIFI / LAN and alert you the connection of unknown devices. It also warns if a "always connected" device disconnects. In addition, it is possible to check web services for availability. For this purpose HTTP status codes and the response time of the service are evaluated.

https://github.com/louislam/dockge
A fancy, easy-to-use and reactive self-hosted docker compose.yaml stack-oriented manager

https://github.com/benjaminjonard/koillection
Koillection is a self-hosted service allowing users to manage any kind of collections.

https://github.com/immich-app/immich
High performance self-hosted photo and video management solution.
https://github.com/mediacms-io/mediacms
MediaCMS is a modern, fully featured open source video and media CMS, written in Python/Django and React, featuring a REST API.