Here's 2-1B, the medical droid who repairs Luke's hand after he loses it in Bespin. 2-1B also fixes his face in the bacta chamber following the Wampa attack. Although the image doesn't show it, 2-1B's feet are bolted to a platform.

The infamous Death Star Droid...one of the first characters to appear as a Kenner action figure. Some of his limbs are similar to the parts used on C-3P0.

An imperial probe droid...it's a good bet the Empire knows we're here. I always felt this droid was modelled after a jellyfish.

This is the torture droid used as a mind probe on Leia in Vader's attempt to discover the location of the hidden Rebel base. It was actually created using two R2 unit "heads" and some surgical equipment.