if there were hostile bots on Fulgora.Defenders that spawn when you mine a vault seems like the easiest to implement.
I have seen others suggest ruins including enemy roboports full of hostile robots that steal your items and place them randomly around themselves. That would be hilarious and doesn't seem like it would be too hard, either.
Any kind of robot also seems like it would be a natural enemy for the electric weapons unlocked on the planet. I would love to zap a cloud of enemy bots!
Thank you Wube good game A+