OpnSense running on an ex-lease HP i3-something SFF desktop. Added several cheap half-height GigEth PCIe cards for the LAN bridge.
It is way over spec for what OpnSense needs but it was cheap and extensible.
UPS power supply.
There's a tangle of PoE injectors which makes me sad. PoE PCIe cards appear to be ludicrously expensive here for no apparent reason.