Simple categories matching obscure:

• instrument,

Members with property obscure:

• harp,
• sitar,
• glockenspiel,
• quint_bassoon,
• metal_plate,
• euphonium,
• theremin,
• french_horn,
• bagpipe,
• bird_call,
• glass_harmonica,
• banjo_ukulele,
• marimba,
• oboe,
• tuba,
• phonograph,
• clavichord,