What's the Best calm neutral wall colors without being boring?

Grey has different types of shades, depending on how light or dark you want

to my taste, I suggest a very pale green, yellow or rose. Gray is still popular, and pale shades of beige are also a good choice.

pale green is meant to be calming

When you go to the paint store look at the paint swatches and decorating books. You will find that almost any color that's muted can be neutral. Think about the colors in your room and keep that in mind when looking a decorating swatches. I also look at nature. Take some pictures of nature and pick out the colors. You will find that pallet naturally appealing.

I love sage green which comes in shades with little to mostly grey. My living area has a very grey green on the bottom called quahog, with a more typical sage color called ostrich on top. The names came from the C2 line of paint.

Popular colors right now are a soft turquois, creams, mint greens. These will surely brighten up without the boring plain look

Is the room dark? I would go for yellow tones. If it is light then blues or greys.

We painted our living room a warm gray. No matter what you put next to it, the tone seems to change. Sometimes more blue, sometimes toward tan.