The spell Druid Grove has an oddly specific material component that is consumed but is otherwise costless: "A mistletoe harvested with a golden sickle under the light of a full moon" (XGE, p.154).
At level 20, an Arcdruid can ignore material components that don't have a cost and aren't consumed (PHB, p.64).
Does that mean that the druid can ignore material components that have no cost but are consumed?
Just have this idea of a high-level naked druid wandering in the forests creating temporary sanctuaries all over. But I don't know whether the druid itself has to have the component for Druid Grove on hand, or can just be completely naked.