When doing art with traditional Media, a popular choice is Pencil. There is a wide range of pencils, in many different types. A very popular art pencil is the Graphit Pencil.
Graphit Pencils are usually made of graphit sticks, incased in wood, but there are some graphit sticks without coating. They come in a range of hardness from 9B, the softest, to 9H the hardest.