I have five shades of Kona and Bella solid grays that work in gradation with solid black, several brands of the black to gray gradation fabrics like Shade Cascade, plus maybe five or six tone-on-tone prints in gray (they go well with my ten or more tone-on-tone blacks). And no, I do not make Goth quilts...I just frequently use shades of black as neutrals! :lol:
Colors I use gray with, aside from black, are pretty much anything. The colonial colors are muted and grayed down and go especially well with grays. Just as any vivid color goes with black, any muted shade goes with gray.