The smallest bots are from hydra too?
I think it's the Minibots - at first I thought it could be the Toolbots from Reaper Chronoscope, but a closer look seems to confirm Hydra.
They're great minis, and well executed. I have a handful that I have to get to work on this winter. I still ponder whether to go for the 'iron' look, like these, or a more blueish steel look, like seen somewhere else on these pages. (I also painted some Terminator Robots with a blue tint, and like it, but I'm not sure about these pulp/retro sci-fi things...)