An electronic drawing pen? It sounds like a novel idea, but if you enjoy stippling and pen-and-ink work, the Dotspen (opens in new tab) is a great timesaver.
There are four waterproof inks to choose from – black, blue, pink and yellow – but allow them to dry thoroughly before applying coloured washes over the top.
The nib itself moves up and down rapidly creating a series of dots rather than a solid line. It's worth having a play to see how moving the pen at different speeds across the surface affects the dots. A long, quick sweep will produce light, widely spaced dots, whereas a slower movement, held slightly closer to the paper, will produce denser dots that look almost solid.
There is great fun to be had with this electronic pen, but illustrators and graphic artists will, in particular, find the timesaving aspect to be of great value.