In my home-spun campaign, players are about to discover the ruins of an ancient city. Long ago, there was a civilization with an advanced level of technology, which is now dead. I'm thinking of pitting them against the remnants of this civilization: their automated traps, fail-safes, etc. and perhaps some of them really survived ;)
What are some examples of "high-technology" traps and monsters in the D&D universe? I'm thinking clockwork/steampunk/magictech flavor. I was looking in the monster manual of 4.0, and found few creatures that fit this description. Golems maybe, and a couple of automatons. I was thinking of "hand writing" a few basic monsters by just changing the flavor of their attacks, but I'd prefer if there was some existing lore I could use.