Simple categories matching stretchable:

• textile,
• fiber,
• fabric,
• synthetic,
• material,
• knit,

Members with property stretchable:

• polyurethane,
• polyester,
• spandex,
• neoprene_rubber,
• polyurethane_fiber,
• elastic_belt,
• flexible_silicon,
• velcro_cloth,
• nylon,
• artificial_leather,
• knit_cotton,
• jersey_fabric,
• stretch_fleece,
• rubber,
• rayon,
• steel,
• paper,
• cotton,
• sweater,
• knit_jersey,
• conductive_fabric,
• latex,
• rawhide,
• leather,
• fleece,
• crepe,
• silicone,
• fabric,
• cotton_tricot,
• latex_rubber,
• stockinette,
• jersey,