I had the same problem so started looking for solids or near solids. I found at Connecting Threads a collection called "Mirage". Its not really a solid as it reminds you of colored cement with 2 or more colors blended in. I've collected the entire series for my stash.
Also in their Neutral Love II they have what's called Faux Linen in 3 shades..browns and greys. Not solid but could pass for one enough. They also have something called "pebbles" which has some dots on it but it could work well enough. I guess you could pass these as tone on tone sort of.