Maybe a very light slate blue or a gray-green. Staying with light colors will reflect more light and make the coloring in the maple wood come out more.

Do you have upholstery you need to worry about, or are you starting from scratch and getting new? Nomadic Desert is one of those warm neutrals that will go with any color, and IMO, it doesn't make any difference if it's warm or cool. My sister recently painted her family room a color close to the ND, and did an accent wall in a rust color~ it looks great, and very cozy.

Laughing about the bathroom here. No, no fancy floor in there. We're not spending much. It was a handyman's special, with about 8 different kinds of tile, a pink (inside) shower, and even some floor tile on the wall. Rusted out sink, uneven floor. A mess. When it's done it will be mostly white, but we will splurge a tiny bit on a Susan Jablon blended glass tile backsplash in blues and a mirrored pin dot. Otherwise, maybe a blue wall or two and some brightly colored towels. My boys are 13 and almost 10 and don't care a lot. I am just looking forward to getting it done b/c I don't like sharing a bathroom!

If you like the darker wood tone of the shelf a wood look tile floor that was lighter but had dark tones in it could work. There is a the risk with the more multi-toned floors to look a bit rustic and that may not be what you are going for. Here is an example of a Home Depot tile Montagna Rustic Bay The picture above is a bathroom that I recently designed that has the wood look ceramic tile on the walls, a more rustic multi-color kind than the home depot link. I think the dark wood colors look nice with grey as well. Even if you are going with vinyl tile, there should be similar options in vinyl. Good luck!