Just read one of the books lol, I’m not a wiki.
Most any of the order aligned races have a pretty well explained culture and religion. Only ones that don’t as well are the death aligned ones, but it varies as you’d expect.
edit: as a suggestion, daughters of khaine and deepkin both have decent twists on old factions, I’ve heard good stuff about cities of sigmar too.
second edit: there’s actually an entire game that’s designed to give a better look at chaos warbands in the setting too, though I’m not as familiar with it