This is probably the silliest wandering I have done, but I got stuck on it after having finished reading The Girl in the Green Sweater: A Life in Holocaust's Shadow
and then seeing a recommendation for The Blue Sweater: Bridging the Gap between Rich and Poor in an Interconnected World
So, I had to find out how many color sweaters exist in English book titles that have nothing to do with knitting or making sweaters. The answer is: too many: