I'm fairly equal-opportunity when it comes to liking giant robots. Lately we've been getting them for both humans and Tau from Games workshop (as well as a few other companies. Well, robots for humans, anyway. I don't think any other companies have put out Tau robots recently). Well, those space elves, the Eldar, are getting their chance to shine with some new Wraith Knight variants over in the Forge World webshop, as well as a new Imperial Armour book.
The Skathach Wraithknights walk that line between here and not, going to the ethereal realm to do battle. The gear that allows them to do that is pretty rare, so you won't be seeing legions of these walking around the battlefield (unless you go out and buy a whole legion's worth, I guess).
Meanwhile, the new Imperial Armour book takes you to Betalis III and the forces that fought there. There's rules for the various combatants, including characters, vehicles, and fliers. Of course, it also has the rules for the Wraithknights. But more than just the big walkers, it's got a whole army list for the Eldar Corsairs.
All of these can be ordered now from the Forge World webshop.