Almost all my character animation is hand drawn so I'll share my stuff too:
All the sprites in this game are drawn and inked on paper. Then I scan it and add the colours in photshop and what not so I can put it together in Spriter. (I haven't touched this game since halloween, it could use some polishing...)
And here is some early experimentation, it's by no means finished.
All the body parts you can see there to the left are hand inked with a brush. Sounds kind of fancy, but it's probably quicker this way for me than to ink it with my wacom. As you can see in the close-up, the lines aren't super smooth, but zoomed out they look fairly smooth. But then, if you want it super smooth, maybe vector graphics is the way to go.