The way I've observed the colored list working here and on the "other" site is they pick a regular color from the marble shading as the base, then the color it is marbled with shows up in the title. https://www.brickowl.com/catalog/lego-red-marbled-blade-90795 is an example (though that one should really say yellow in the title, hmmm).
Comments
The Grangemouth bricks and those slotted brick changeover/waste material examples are some of those items.