Per capita probably Netherlands, if we only count MMA (Bas Rutten HW champ, de Randamie (WFW champ), Reinier de Ridder is the current undefeated (15-0) MW champ in ONE, Overeem, Mousasi and Marloes Coenen, Manhoef were champs in other organizations like Strikeforce and Bellator., in kickboxing...