In modern quilting, neutral background colours are often white and grey. Kona White, Snow and Bone being really popular in the whites and Kona Ash being the most popular grey.
In the colour intensive course I did with Stiched in Color, Rachel Hauser gave us White, Black, Grey and Brown toned colours as neutrals. Some of those tones are cream, champagne, beige, and tan. I know modern quilters usually shy away from brown but when used with bright colours like yellow or neon green it can really work! Try thinking of brown as dark orange and maybe you might use it a bit more?
Instead of the starkness of black I have loved using Kona Navy and for a while seemed to making only navy based quilts!
From time to time I get bored with solids and go low volume too for a change - I think low volumes fall into the neutral category!
This past year I have really enjoyed playing with colour trying out Charcoal, Iron & Steel, Orange, pale Blues like Fog or Cotton Sky and even loved the darker purple-grey colour of Smoke.
I stumbled across a free download by Lila Rogers of Make Art that Sells and she identified the neutral colours to include that ground artwork as:
• Cool grey
• Sky grey-blue
I am happy to say that in the last year most of these I had tried but not Olive or Red. I'm liking the look of Olive so maybe that might be the next colour exploration. What about you - any go to neutral you use all the time for your quilt backgrounds? Tempted to try any of these?