These were two quick concepts I did for a friend's game. The setting is FAR post-apocalyptic. These were two of the first factions:
On the right, an Imperial society with some records and traditions of the pre-destruction past, but resources and technological capabilities only up to steel-working. So, I went for a blending of modern military/SWAT styles and Roman or Medieval materials.
On the left are the Wild men, which have diverged genetically as larger, rougher folk. Culturally, they have no ties to the pre-destruction past, and low technology, so they use the ubiquitous remnants of the past as pure raw materials.
It was a fun quick pass. I hope he continues it and we can expand on these, and do some of the other factions.