Like many people, I try to reuse paper from my printer. Instead of just throwing away a piece of paper with something printed only on one side. I tear it into quarter sheets to use the unprinted backsides as note paper. These can be just written reminders.
Little mindless doodles are also something I quickly scribble down on the back of the scraps of paper stacked at the corner of my desk.
Here are some recent ones pasted together, sumo wrestlers, oni, hair, and a giant grub.
scanned pencil sketches