Numi Organic Tea
Numi designs the plastic out of the steeped bag. The filter is manila hemp (abaca) and wood-pulp paper, closed with a "crimp and knot" process that Numi says specifically eliminates the polypropylene most brands use to heat-seal a bag shut. The string is cotton, the tag is recycled paper with soy-based ink, and the bag is BPI-certified compostable.
The remaining plastic is in the outer wrapper, not the bag: Numi's individual overwrap is a paper/cellophane/PLA laminate. That is packaging you throw away, not something your tea steeps in.
How clear are their specs?
Publishes a full construction breakdown (bag fiber, seal method, string, tag, overwrap) and says it holds supplier certification that no plastics or microplastics are added in manufacturing - among the most transparent tea brands on materials.