Monochromatic painting, subject ideas.?

[WINGMAN]

This is for a friend.
I am an art student and my favorite media is watercolor.
I am learning how to do Monochromatic Painting.
I use Burnt Ciena and Ultramarine blue for colors,
separately of course.
I have painted farm buildings, flowers and birds.
I was wondering if somebody had some ideas for other subjects
that I could paint.
Thank you.
Wingman

 

[le petit poucet]

Subject is everything, everything is a subject. Pick one.

 

[ABCDXYZ]

townscapes, people, self portrait, everyday things, anything that suggests action.