I have a couple of huge schoolhouse maps, the kind that pull down like a window shade. Each one is about five feet across, very colorful, only $60 each at the junktique shop. A really powerful quilt would also work. Or a supergraphic painted directly on the wall. Or stencils. Or take some photos, and blow them up to huge size at a reprographic place. Maybe a photo of each person in the household, blown up to at least 3' x 3', then stacked vertically. In fact just repainting with more color would do the trick. That way you can wait for the perfect thing, instead of just buying random items to fill the empty space.

I like the art and like the space but I think the aesthetics of each would be further enhanced if they were independent of each other. I would just get all or part of the painting group to paint one or more canvases scaled to size that include some lighter neutrals, and pass on the two larger boldly colored paintings to a space that has more of a Modern style and is better scaled to their size.

There are lots of great suggestions here. I love the idea of the black towel ladder and the shelves above the toilet Personally, I support the idea of art on your walls and I love your pallet. I understand the comment of selecting art/pictures via colour scheme. but I am going to suggest a different way of thinking about choosing art for your bathroom/ home. It may take time tho, to followup on my suggestions if you consider following them. I would just like to add that I grew up in a home that was filled with beautiful art. My parents could not afford the 'real' thing so my Mom cut beautiful pictures out of magazines, framed them inexpensively as she could, and hung them in groupings on our light pained walls. First your bathroom pallet is calm and restful. It will not compete with most art that you choose, but instead will create a back drop for the art. I see art as a relationship with you and the art. Art is personal and meaningful. I would scour art galleries and their artists on-line and in your area to see what type of art appeals to you and your husband. ( see note below) After finding out what you like, you may purchase a piece from a gallery, furniture store, an art auction ( fun!!!!!) , or grad shows/sales for art schools. ( I paid 300$ for one pice that I bought from an art school sale,) or painting guilds. If the art talks to you , it is is a sign that it belongs in your house. Good art stands on its own and does not need to be expensive and also just needs a neural backdrop to show it off. You have the neural. Generally people are consistent in choosing art they relate to, so the pieces you choose will have some consistency. What matters also is the space and placement ........you have to place your art. For above the towel rack, I would suggest a piece no wider than 5" on either side the of the towel rack and no higher than the top of the mirrors. If the art is wider, then it will not be "supported" and then it will add tension to the room. I'd suggest placing a piece of art between the mirrors . I would suggest that it be higher than the light switch, slightly lower than the lights in the light fixture and 4"to 6" or so from the edges the mirrors. I'd also put an art piece above the toilet. But that is me. I don't mind living in an art gallery look. If you are considering art just because you think might be a suggestion , but you love clocks, I think you should choose clocks. If you love clocks tho, than you would be following your heart and then I'd suggest you look up clocks on Houzz and see what people are doing as they decorate with clocks.I'dd recommend one clock between the mirrors, : fram the mirrors. and a grouping over the town rack and then place shelves over the toilet. CB2 has clocks, Chintz also had great clocks. Note: My contractor's wife said she and her husband had different art tastes, so I worked with them by listening to what they liked in art and looked for art on gallery websites. Long story short. I sent them images art that combined what they liked and they ended up choosing a piece that they both loved. On the other hand you both might like the same art or one of you might not care so you would have an easier task. I have a framed batik under glass, a stretched giclee canvas and a framed under glass relief in my two bathrooms and have has no issue with moisture from the showers /tub. If you don't put art between your mirrors I would recommend framing them. food for thought............

I have no help to add about the art but I do love the colorful rug @celery showed I the last post. Something dramatic with that gorgeous green in it will tie the room together. Your dining table is stunning! And the green chairs are a happy surprise ( most dining rooms have all chairs the same).