Ethernet will probably do fine. The differential pair ends in a transformer, so unless you pump so much current in that it physically melts the transformer or wire, you'll be fine. USB should be similar, but apparently is not. (In the case of the USB killer, the amount of time where 200V is applied to the circuit is probably very tiny. I imagine it's just a charge pump that charges a tiny capacitor and discharges it.)

Ethernet is designed this way because the differential pair can apparently pick up a bit of a DC bias when laid next to cables in the ceiling/wall. While researching this post, I found that the spec requires the transformer/inductor to work correctly with a 30mA bias current. I am too lazy to go measure what the DC resistance is, though, so I don't know whether or not 200V is close to that.

When I was in high school, I wired up a cat 5 cable such that each pair was connected to one phase of the mains. I then plugged it directly into my iMac. There was no damage to the computer and the Ethernet port worked fine afterwards as well. (The integrated monitor went crazy; this was in the CRT days and presumably the Ethernet transceiver's magnetics make a good degaussing coil).