Does anyone else use old equipment for homelab use? If so, what are you running?

A few years ago I had a couple old and slow Optiplex's running Hyper-V, with Windows/Linux VM's, doing things like NPS, AD, etc.

Had some old equipment collecting dust, so I've built out a decent homelab and am curious if anyone else has done the same, and if so what are they running on them for fun?

In my new "rack":

• PowerEdge R430
  • Running ProxMox, with a Windows VM (DC), and a Linux VM with Docker for Plex
• EqualLogic PS4100
  • VM storage for both PowerEdge servers (10TB)
• Ubiquiti EdgeSwitch 24 250w
• PowerEdge R720
  • Running ProxMox, with some Linux VM's, most utilizing Docker for Plex "assistance/automations" (ahem), NextCloud for phone photo backup and wife's photography, and another DC as a failover of R430's DC.