homelab

Total e-waste and a power draw. Even a Raspberry Pi 4 Model B can beat it to oblivion:

https://browser.geekbench.com/v6/cpu/compare/6390478?baseline=5583060

Your primary issue is going to be the power draw. If your electricity supplier has cheap rates, or if you have an abundance of solar power, then it could maybe find life as some sort of traffic analyzer or honeypot.

But I think even finding a PCI NIC nowadays will be rather difficult. And that CPU probably doesn't have any sort of virtualization extensions to make it competitive against, say, a Raspberry Pi 5.

E-waste

Best use is ewasting it because of power draw.

Does it have onboard graphics? It will be hard without that. If it has, you can make a vintage arcade machine, but with multiple games. You could, for example, run linux with OpenTyrian on it, which is one of my favorite games. Xgalaga++ and a lot of old games with DOS emulation should also be possible. You can strip down the OS, so only the barest minimum runs; should save some RAM and CPU.

It's not power efficient, you're better off buying a cheaper computer, that runs on far fewer watts

If you want to run it as a museum piece, or for archaeological purposes, go for it.

You could run it as a router, I question how much throughput you can get... But again, a cheap $20 off-the-shelf openwrt router like gli.net will be much cheaper on your power bill.

I don't know how much your electric rate is, but a router or server that sucks down a hundred watts 24 hours a day may be a concern. An arcade machine would be my choice.

N100 mini computer with five Ethernet ports make a good router. And can be bought for around $100 USD.

You could use it for Windows 98/XP retro gaming if you add a graphics gard, but for anything else it's far too inefficient to be useful