In script.. No. filtering can filter on color, but color can be defined from defined filters. and you can filter on defined filters..
Is there something like "label:" or something in Filter Box I can use to filter out all the 'Color Rules' items for example ?

So there's no Filter Box command syntax to narrow down to only Color Rules ? This would be very convenient for me to list every Color Rule by filter.
P.S: I found out how to do it by selecting a single Color Rule file, pressing Ctrl+Shift+Num+ (Select by Color) then pressing Ctrl+G (Ghost Filter.)