Simple categories matching harmless:

• pollutant,
• particle,
• animal,
• substance,
• critter,
• constituent,
• compound,
• ingredient,
• spider,
• activity,
• thing,
• creature,
• rodent,
• crime,
• material,
• powder,
• salt,
• residue,
• metabolite,
• metal,
• foodstuff,
• disorder,
• item,
• preparation,
• preservative,
• task,
• sugar,
• solid,
• insect,
• object,
• agent,
• bird,
• being,
• bug,
• gas,
• carrier,
• allergen,
• liquid,
• prey,
• fluid,
• medication,
• matter,
• drug,
• neighbor,
• food,
• contaminant,
• plant,
• souvenir,
• chemical,
• stuff,
• snake,
• antigen,
• component,
• organism,
• impurity,

Members with property harmless:

• dust,
• water,
• insoluble_salt,
• soy,
• diadem_snake,
• agouti,
• butterfly,
• mold,
• food,
• hydroxide,
• insect_venom,
• wheat_protein,
• ibuprofen,
• recitation,
• nitrogen,
• silk_bonnet,
• rabbit,
• metal,
• ant,
• spider,
• caffeine_pill,
• deer,
• chalk,
• royal_python,
• starch,
• bicycle,
• ballast_stone,
• wallpaper,
• milk,
• cheese,
• lactose,
• open_book,
• ugly_clothing,
• weed,
• cat_litter,
• pigeon,
• extortion,
• telephone,
• spice,
• wheat,
• traffic_helicopter,
• shellfish,
• paintbrush,
• joint_advertising,
• frog,
• prank,
• lie,
• curlew,
• paper,
• sulfa,
• movement,
• oxygen_gas,
• inactive_pill,
• lipstick,
• calf,
• radioactive_compound,
• lizard,
• tweezer,
• flower,
• co,
• cigarette_pack,
• nicotine,
• cup_holder,
• bird,
• potassium_sulfide,
• ethane,
• huntsman_spider,
• semolina,
• common_salt,
• uric_acid,
• antimalarial,
• driftwood,
• inert_gas,
• beetle,
• acetaminophen,
• language,
• schooner_sail,
• registry_key,
• reading_email,
• diesel_fumes,
• titanium,
• goldfish,
• particular,
• funnel-web_spider,
• nitrogen_gas,
• yeast,
• nail_clipper,
• pineapple,
• marijuana,
• cockroach,
• pea,
• powdered_sugar,
• chloride,
• content,
• cauliflower,
• day_trading,
• tweet_bird,
• powder,
• monarch,
• cork,
• alcohol,
• bull-snake,
• pharmaceutical_compound,
• urea,
• meteor,
• dolphin,
• cows,
• wood_carving,
• noble_gas,
• ostrich,
• dust_particle,
• dancing,
• carrot,
• kingsnake,
• crowd,
• potsherd,
• baby_walker,
• soil,
• elemental_hydrogen,
• vinegar,
• animal_fur,
• aged_cheese,
• ethene,
• meat,
• antihistamine,
• plant_extract,
• mold_spore,
• jeep,
• drink,
• salt,
• glucose,
• small_dog,
• fertilizer,
• wire,
• plastic_slug,
• wallet_chain,
• bathing,
• small_snail,
• aluminum_powder,
• aqueous_co,
• vulture,
• tick,
• leaf,
• certain_food,
• bat,
• newspaper,
• inorganic_chloride,
• pesticide,
• paper_label,
• carbon-dioxide_gas,
• box-elder_bug,
• link_building,
• sulfate,
• medication,
• bones,
• brownie,
• various_food,
• cloth,
• new_toy,
• crushed_cork,
• straw_waste,
• glass_marbles,
• caffeine,
• hummingbird,
• house_dust,
• fly,
• cacique,
• smoke,
• cellophane,
• chlorine,
• iron,
• llama,
• mouse,
• market_survey,
• granite_tile,
• dark,
• wasp_venom,
• cartridge,
• hydrogen,
• spinach,
• corn,
• liquid,
• white_sugar,
• zipper,
• toad,
• adhesive-tape_help,
• mosquito,
• stew,
• dirt,
• duck,
• food_constituent,
• building,
• hissing_cockroach,
• balloon,
• driver_type,
• heron,
• baby_shampoo,
• air,
• gasoline,
• light,
• nail_scissors,
• use,
• rhubarb,
• book,
• plywood_waste,
• alkali-metal_salt,
• statue,
• plastic_bottle,
• baby,
• monkey,
• cannabis_derivative,
• reading,
• rosemary,
• helium,
• blind_snake,
• grain,
• insect,
• co2,
• pollen_grain,
• stork,
• shampoo,
• mongoose,
• hardware,
• accessory,
• olive,
• woodlouse,
• potash,
• myna,
• fawn,
• oxygen,
• papers,
• suitcase,
• pram,
• antibiotic,
• peyote,
• large_ammunition,
• chemical,
• grass_pollen,
• salt_particle,
• prostitution,
• christmas_play,
• drug,
• inert_filler,
• military_science,
• bunny,
• penguin,
• methane,
• jewelry,
• writing,
• pencil,
• turtle,
• black_beetle,
• rice,
• juice,
• medicine,
• fruit,
• water-vapor_gas,
• hemp,
• thrip,
• yoghurt,
• organic_compound,
• viral_infection,
• plastic_spoon,
• pan,
• parrot,
• repetitive_movement,
• handcuff,
• cream,
• boarding,
• doubt,
• macaw,
• water-vapor_h2o,
• manatee,
• evergreen_branch,
• bulletproof_jacket,
• hypochlorite,
• dugong,
• football,
• cement,
• pollen,
• perfume,
• egg,
• elephant,
• plant,
• bath,
• nitrate,
• pet_droppings,
• string,
• aspirin,
• sheep,
• cat,
• felt_pen,
• specific_food,
• animal_dander,
• hydrilla,
• playing_hopscotch,
• clay-pigeon_shooting,
• small_monkey,
• loose_mat,
• household_plant,
• cfc,
• thunder,
• cigarette,
• springtail,
• ball_python,
• talcum,
• dragonfly,
• sulfur,
• hamster,
• food_protein,
• scarlet_kingsnake,
• pet_fur,
• camel,
• open_place,
• carpet_glue,
• lacewing,
• antelope,
• oxide,
• gecko,
• stick,
• alum,
• lsd,
• latex,
• nail,
• h2o,
• lignin,
• environmental_antigen,
• key,
• scented_tissue,
• cell,
• paying_bill,
• paint,
• moth,
• street_football,
• fire_break,
• food_ingredient,
• starch_powder,
• squirrel,
• tranquilizer,
• sugar,
• vase,
• dust_mite,
• sedative,
• zebra,
• instant_messaging,
• walkman,
• pot,
• earwig,
• jewellery,
• insoluble_sulfide,
• preying_mantis,
• cannabis,
• aerosol,
• lawn_clipping,
• satyr,
• brine,
• button,
• propene,
• raven,
• cardboard,
• tumbleweed,
• exercise,
• closed_place,
• chipmunk,
• tomato_vine,
• radio,
• sand,
• zinc,
• new_picture,
• small_cat,
• ethyl_cellulose,
• carol,
• inorganic_salt,
• fruit_powder,
• dangerous_smoke,
• lighthearted_proverbs,
• drywall_dust,
• child,
• vitamin,
• helicopter,
• robin,
• decongestant,
• ladybird,
• coca,
• paint_remover,
• rural_development,
• glue,
• writing_exam,
• propane,
• thread_snake,
• online_auction,
• hydra,
• yogurt,
• beverage,
• stuffed_animal,
• oil,
• staple,
• allergen,
• household_dust,
• pen,
• worm,
• cornstarch,
• dog,
• ammonia,
• dangerous_toxin,
• giraffe,
• grass,
• pet,
• tortoise,
• carbon,
• pig,
• battery,
• tonic,
• cookie,
• seafood,
• crow,
• dove,
• grapefruit,
• lemur,
• recreational_activity,
• animal,
• nail-polish_remover,
• toy,
• fish,
• ethylene,
• new_item,
• sand_boa,
• aluminum,
• songbird,
• cooking,
• reed,
• regular_air,
• potato,
• food_antigen,
• jewel,