Light gray walls, white ceiling and trim, and pops of red, yellow, orange, green, or lavender. Or some combination of those brighter colors in accessories.

Mellow yellow or light green

These are Sarah Richardson nurseries. What I like about hers is that she takes into consideration the parents in the design. This is a room that the baby will not remember. So why not cater to the parents' sensibilities too? When they are toddling around, learning their first words, then start gearing room slowly towards toddlerhood. Meanwhile go online or on Houzz and search nurseries. Then you can tell us what your preferences are!

https://www.houzz.com/photos/gender-neutral-nursery-ideas-phbr1-bp~t_12299~a_51-394

Greys and whites are very popular right now, and they are also a great neutral base color. If you pair greys and whites with gender-neutral colors like yellow and green you can make a really wonderful nursery. Beyond the general color scheme though, the possibilities are endless. Ikea has some really great cloud shaped pendant lights that would look amazing in a nursery, or for a more traditional look miacometlady posted some amazing pictures. Just keep in mind that there is a lot more spit-up and diaper changing going on in a nursery than you might expect, so make sure everything is washable :)

My children are in their 40's and then we did not know the sex of expected babies! We usually did a pale yellow and white nursery and it was lovely. I like a nursery to look like a nursery. One can later add primary colors as the child gets older, but a baby is a baby for only a short time. In my 2nd grandson's nursery, we painted the walls a pale yellow, and had an antique white wicker bassinet with yellow satin ribbon run through it. The liner was a quilted white fabric and the skirt was heavily gathered white dotted swiss. The shades were already in the room - made from Souleiado sheets (think Pierre Deux), so when the crib was set up, it had a white linen dust ruffle that we had made. Very pretty.