I took an excellent online course with Von Glitschka awhile back, called the 21 Day Drawing Challenge. One of the prompts is to draw an image without lifting the pen. Just one intuitive, free-flowing line. It has been such a fun activity for me, and it really captures the something-from-nothing feeling that I can get when I create. If you ever feel stuck or concerned about perfection, I encourage you to try it.
Some of my recent all-one-line drawings are below. To see posts of other artist's #alloneline drawings, search the hashtag on Instagram. Cool stuff.