A polymer fiber that contains carbon nanotubes and reduced graphene oxide is stronger than Spider Silk and Keuler. The most robust polymer yarn of all time has been made by mixing a graphene oxide, and carbon nanotubes during Kato Polyclay are also one of the most durable polymer clays on the market.
Spider Silk is also a very strong polymer. Wood is also a solid polymer. The parallel strands of cellulose fibers held together by a lignin binder. These long chains of fiber make the wood exceptionally strong.