A somewhat ambitious double bounce walk cycle I started over a year ago but never finished, loosely based on Graham Specter (Baccano!).
Back in the days before rendered 3D elements became acceptable in animation, animators would often render 3D objects (such as cars, mechs, environments, etc), print the frames and creatively 'trace' over them with pencil. This method saved you from pulling out your hair over perspective accuracy, but still allows for some creative license and imperfections inherent to 2D animation. This method has been largely abandoned now that 3D elements can be more seamlessly integrated with 2D animation, but I find that even when it's done well (and often it is not) it still lacks the aesthetic quality that a human hand manually rendering the frames gives.
So I modeled, animated and rendered a 3D 'guide' with Blender to help with the fisheye-lense perspective, then imported it into Krita where I was going to animate the character and background in a 2D workflow. I gave up due to my drawing ability not keeping up with my vision, but I think sooner or later my drawing skills will be good enough to go back and finish this properly.