I don’t know what the “white American collective imagination” retains of native and aboriginal peoples… Not much, it seems. but in Europe, we generally are fascinated by the First Peoples !
I think there would be great developments to be made through “tribal/ethnic” lines, not ?
Afghans, Zulus, Somalis, generic warriors and Aztecs are done : by Perry, Victrix, Frostgrave and WGA… Good lines. What else ?
Warriors from the cold, like Inuits and Samis ; northern American warriors from the forests (Hurons, Iroquois, Crees), from the “prairie” (Lakotas, Cheyennes, Pawnees), from the “sierras” (Apaches, Navajos, Utes), warriors from the Pacific area (Tlingits) and from Dixieland (Seminoles, Cherokees) ; warriors from Central and South-America (Mayans, Incas, Caribes, Amazonians and Mapuches) ; African other warriors (Masais, Tuaregs ?) ; warriors from the Far East (Siberians, Thais, Taiwanese aboriginals) ; Polynesian ones (like Maoris), and so on…
… with the possibility, for some of them, to be worked on by bringing a Sci-Fi touch !