Simple categories matching blue:

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

Members with property blue:

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