I had one that I pulled from an ewaste bin. Ran Linux and used it as a file server and to run Foundry virtual tabletop. It was fine for that.
The file permissions got all fucked up some how and I wanted to learn docker so I upgraded to an optiplex 5090 with an 11th gen CPU for more horsepower.
What does your home network need? It could run DNS or DHCP pretty easy if your network is big enough for that.
File/print server. Media server, though the older Intel chip might suffer with encoding streaming video.
Intel has a pretty cool AI extension for Audacity. You might be able to set it up as a little music production station but it might be a little underpowered for that.
If you had a big central hypervisor you could set it up as an RDP dumb terminal to connect into a VDI. Probably a pretty long shot.
Speaking of a hypervisor, there might a hypervisor software that would let you cluster them together. Again probably overkill for a small home network unless you're really into that shit.
proxmox runs on basically everything so there is that but yeah. All good suggestions.