The GNU Image Manipulation Program is an open source photoshopesque thingy which does a whole lot more than your standard cellphone editor. Most importantly its free.
Blender allows you to create animations based on the movement of armatures (somewhat like bones). What that means is that you make the 3d character once, then move its ‘bones’ and blender makes the ‘skin’ move along – 5 seconds per frame instead of 5-10 minutes. Trouble is, how does one turn that up there into a line drawing? Immensely complicated node trees seems to be the usual answer but somehow I have managed to stumble onto a rather simple method (most of those nodes are for adding the colour)
Lit by setting sun
moment in eternity
snail’s eternal pace