I love these kinds of threads!

Our
master bathroom is light purple (walls) and white (most everything else) with a few little touches of green and soft colors. It is a small space, roughly 6x9 total. I store the washcloths rolled up on a wicker shelf. I store toiletries in the master closet in a cabinet I already had. We have a double towel rack on the wall and an 8-hook rack over the door and two robe hooks on the back of the door.
Our
guest bathroom is brightly festive with aqua walls and a very colorful shower curtain and framed single, bright, colorful flower prints (greeting cards) on the walls. We don't really need any storage in this bathroom yet. It is DD's bathroom and eventually we may need something further. For now, she has her hooded towel on a hook next to the main towel rack and two robe hooks on the back of the door. This bathroom is identical in size and shape as our master bath. The only difference is this one has a tub/shower and ours is just a full-size shower (no tub). They are both tiny (approximately 6x9, ceiling measurement, not floor

).
Our
powder room is a deep cranberry color (walls) with white main items and a few splashes of bright cobalt blue (color that runs throughout the downstairs) and a big bunch of sunflowers. It is tiny (3x8), but feels more comfortable in the deep cranberry than it did when it was "swiss coffee" (off-white that may as well be called "dirty white"; DH always thought it WAS white... LOL). The laundry room is between the hallway and the powder room and the laundry room is a rich, creamy off-white (Innocence by Behr) that is definitely NOT white. White trim looks great with it. Anyway, the effect of the deep cranberry set way back is really nice as an accent wall to show off one of my favorite paintings that we framed ourselves (as in made the frame from raw materials).
In all cases, we utilize vertical storage on the walls and doors. Good luck!