• Jellyfin - film/tv, both locally and on a seedbox.
• stable-diffusion-webui - self explanatory
• Matrix/synapse - private instant messaging for myself and tech minded friends
• MeTube - web UI for youtube-dl
• Stash - like Jellyfin/Plex but for any adult media you may have (link is SFW).
• Lemmy - only privately just seeing how it all works, I don't intend to make a public instance.
• A fairly typical LEMP (Ubuntu, Nginx, MariaDB, PHP) stack on my VPS

Stuff I used to use or have at least tried out:

• Plex
• Calibre-web
• Typical LAMP (CentOS, Apache, MySQL, PHP) stack back in the old days (PHP4/5) when I did a bit of web dev.