I just beat a game playing as the Cultists. I hadn't tried them before, so I was scratching my head a bit as to what I was supposed to do with them resource wise. I lucked out by starting in a region with both beginner resources, but I didn't have any of the higher tier resources. Since they can't establish new cities and each time they conquer a city they automatically raze it I wasn't quite sure what I was supposed to do. I haven't paid much heed to the barbarian villages before, but the answer to my problems lied with them. There was one village that produced 0.5 of all strategic resources each turn, so I got new resources slowly that way, but that wasn't my main discovery. I hadn't realized that the villages produce new units on their own every X amount of turns (and they don't cost seem to have any upkeep cost either so that's pretty huge) which you can either hoard for an immense army or you could sell them to slavery for a huge amount of dosh. I never really paid attention to it before, but some troops are worth a lot of dust. This works especially well with the Cultists since their gimmick is that you can enslave any barbarian village despite not having a town in the region. I was cashing in more than 10k dust in a single turn which I could spend on the market place to buy the strategic resources I needed to outfit my troops. It's not as sustainable in the long term as being able to properly mine them is, especially with the way the market place adjusts its prices based on demand, but it is a very good way to produce out a bunch of powerful troops in no time at all. It's fun to play a strategy game where you keep finding new hidden depth each time you play it.
Also discovered that the Roving Clans cities are giant beetles with cities on their backs, which means that you can move your cities around if you feel a need to do so. Quite cool.