Since I was a kid, I have always been fascinated with single line drawings. The whole idea of a drawing that has no shading, detail provided by pencil lines. What motivated me was the fact I am not a strong drawer. However, single line drawings are the easiest form of drawing to do, especially for novice artists.
The most beautiful thing about them is you don't have to use pencil and paper. If you have a pen and tablet, you can draw these in Photoshop or any other editor.
When you limit yourself to a singular form of creation, you can surprise yourself with what the outcome is. The thing with single line drawings is they have an amateur charm about them, but also level of proficiency that comes with learning to master them.