For the spider mech (modeled by Shiva3d on TurboSquid), I've created a rig to make it an animation-ready asset. The rig has easy-to-use controls for each part of the model, such as the legs, the wings, the fangs and the direction of the lower body. The piston-like connections between the legs automatically adjust when positioning the leg. As animator, you have a choice of using forward kinematics or inverse kinematics, or you can even blend between the two. The wings have automated and adjustable noise, as well as a controller to open or close them. When closed, they're neatly folded away below its elytra.
This rig has been made in 3ds Max in 1 week. Using bones, helpers and MAXScript, I was able to customize the controllers to have logical contstraints, without limiting the animator too much. Each controller is customizable, such as the amount of noise in the wings, or the use of inverse or forward kinematics per leg.
As this is my first rig, I learned a lot about how bones interact with each other, as well as how to create a rig for a somewhat complex model. The model is also skinned, but most of it is hard skinning. Besides that, I now understand constraints better, and know how to add custom attributes to a controller.