I've used nylon rope, cotton rope, and even hemp ropes for baskets like this. The type doesn't matter as much as that. It makes you happy, and you like the results. My preferred style is more rustic ...

Eric Frattini, The Uru Expedition led by Kitin Muñoz, 1988. Aimara artisans working over the scaffolding of the reed raft in Punta Negra beach, Lima. Private Collection. Courtesy of Eric Frattini ...