Collecting some examples

[kilroy]

 I'm building a list for analysis. I need twenty or so good universes of any fictional variety that have a bunch of persistent, politically relevant factions with different cultures and/or goals. Help me out?

Things that are good examples:
Avatar: the Last Airbender
Babylon 5
City of Heroes
Defiance
Discworld
Dune
Most well-constructed Dungeons and Dragons universes
Erfworld
Feng Shui
Game of Thrones
Star Trek: Deep Space Nine
Any White Wolf universe (including Trinityverse)
The Wire

Things that probably aren't good examples:
Star Wars-- it basically boils down to Rebels, Imperials, and Criminals. There are a bunch of alien races, but they all more or less fall into one of those categories. See also Firefly.
Doctor Who-- you get to see a lot of different cultures and factions, but the ones that show up multiple times are usually just villains or backdrops. Designed as an exploration/showcase rather than an integrated universe. See also TOS and to an extent TNG. 
Harry Potter-- the universe has some breadth and depth, but the story as told essentially boils down to everyone-versus-the-bad-guys. The different strengths of the good guy alliance are largely irrelevant. See also Lord of the Rings. 
Fables-- this actually goes too far into motivational territory, where every individual character has an agenda and even people nominally in the same group have only surface-level common ground. See also most superhero universes, Justified, Once Upon a Time, and Amber. 

Comments

[grammarwoman]

Farscape is a maybe, because they certainly come across a variety of cultures and politics. I would offer as a stronger example (because they actually dive deeply into the notion of politics and culture) Lois McMaster Bujold's Vorkosigan books. (SO GOOD! If you haven't read them, you totally should.)

Or (and I feel sheepish mentioning this) the Stargate collection of TV series.

[korafox]

I will second the recommendation on Stargate, at least SG-1 (I haven't seen SGA).

[kilroy]

My understanding is that SGA continued the tradition in this respect. Either way it's a valid call.

[kilroy]

I think I read three Vorkosigan novels at the behest of a former girlfriend a lifetime ago, but they just didn't do it for me. The Chalion novels, on the other hand, have my undying affection. :-)

[grammarwoman]

If it was forever ago, you may very well want to give them another chance. Or just skim the Wiki entry to get an idea for your examples.