Lots of stuff! Currently running almost all of these in Docker on a Synology NAS:
Code Server - access my notes files remotely
Gitea - only used to store notes that are edited in Obsidian (or Code Server as mentioned above)
Home Assistant - home automation
Homebridge - used for one or two devices that have better integrations than natively in Home Assistant
Jellyfin - video streaming platform (installed because it’s FOSS and seems interesting, but I rarely use it)
Overseerr - user-request app for video streaming platform (installed when I anticipated sharing my movies/shows before realizing that my ISP severely limits my upload speeds)
Pi-Hole - block all ads network-wide
Plex - primary video streaming platform
Radarr - download movies
Readarr - download books but have had better luck with Libgen on an ad-hoc basis