Flintridge/Gorham - Flintridge China produced a wide range of fine china dinnerware, with both solid colors and patterned versions. Based in Pasadena, they have produced china for a fairly long period of time. The company began in the 1940s to 1970 or so. They were purchased by Gorham who repurposed many of the lines and items. The china itself is said to have rivaled the top names of the day.
Many pieces are found in a single solid color, perhaps with white, and often gilded with silver or gold. Floral and other patterns are sometimes found, though I’ve read that those are less popular. It seems correct, as there are many examples of solid color items in stores but hardly any patterned ones.
Flintridge is often marked with a gold leaf stamp on the bottom - but there are full sets with no markings whatsoever. I’m not sure if they originally had a paper sticker, or if there was never any marking to begin with.