I'm working my way through the exercises in this excellent book. Here is an example.
This exercise was exploring making marks with a variety of drawing tools. I didn't have any of those listed by brand name in the book, (many more than are shown here) but fortunately there were images of the tools in question, so I found the best substitutes I could.
The surprise for me was how much I enjoyed drawing with a dip pen - and how much drawing you can do between dips, although considering that we still used dip pens when I was in school, I should have known!