Seaweed, specifically Brown Algae; Yes we know it’s not technically a plant.

Ascophyllum nodosum (often referred to as knotted wrack, rockweed, or Norwegian kelp) is a large, common cold water seaweed or brown alga (Phaeophyceae) in the family Fucaceae. It is a resilient part of the marine ecosystem in the cold waters of the North Atlantic, growing on the shores of several countries.

Highly valued across multiple industries as a natural biostimulant for plants, it is a nutrient-dense dietary supplement for humans and livestock, and a dental aid for pets.