Simple categories matching blue:

• crystal,
• fish,
• decoration,
• box,
• fruit,
• flower,
• diamond,
• cheese,
• berry,
• figure,
• food,
• object,
• material,
• plant,
• indicator,
• state,
• stain,
• item,
• subject,
• symbol,
• pigment,
• color,

Members with property blue:

• blueberry,
• plastic,
• raisin,
• raspberry,
• cookie_container,
• speedwell,
• tablecloth,
• gorgonzola,
• sardine,
• hat,
• pilchard,
• blackberry,
• beetroot,
• saury,
• grape,
• cardboard,
• strawberry,
• butterfly_pea,
• gay_marriage,
• ocean,
• metallic_foil,
• marker,
• feather,
• flag,
• purple_grape,
• plum,
• radish,
• fig,
• gentian,
• egyptian_blue,
• cloud,
• wild_huckleberry,
• scabiosa,
• cherry_popsicle,
• black_currant,
• prune,
• delphinium,
• chrysanthemum,
• swordfish,
• car,
• cranberry,
• food_service,
• blue,
• cherry_jello,
• ageratum,
• pomegranate,
• cherry,
• elixir,
• white_bloom,
• ruby,
• red_petunia,
• tile,
• block,
• bilberry,
• american_blue,
• silver,
• blue_clothespin,
• ultramarine-blue_pigment,
• blue_foil,
• bonito,
• stilton,
• mackerel_pike,
• california_split,
• cardboard_box,
• ribbon,
• white_dwarf,
• blank,
• number,
• balloon,
• aubergine,
• dishwasher_bottle,
• milk_carton,
• cotton_blue,
• violet,
• indigo,
• boysenberry,
• straw,
• crayon,
• scarf,
• anchovy,
• trout,
• fresh_sardine,
• lolly,
• cordial,
• square,
• eggplant,
• grape_soda,
• powdered_blue,
• drinking_box,
• blue_eyes,
• bluebird,
• metallic_blue,
• coloured_glass,
• stemless_gentian,
• bottle_top,
• carnation,
• tuna,
• pen_top,
• diamond,
• purple_cabbage,
• bottle,
• roquefort,
• herring,
• daisy,
• red_grape,
• hope_diamond,
• peg,
• mineral_blue,
• aster,
• blue_rock,
• berry,
• salmon,
• bluebell,
• purple_plum,
• wild_blueberry,
• juice_container,
• vase,
• banner,
• mackerel,
• cruel_barb,
• mass,
• turquoise,
• aquamarine,