Is that everybody fits into all of them a little bit. I'm super Vorthos and we don't talk about mtg very often, so I'm afraid you'll have to indulge me for a moment, because I really want to break this all down.

Azorius: A bureaucracy headed by otherworldly geniuses that establish the rules for the rest of Ravnica/the PPC in order to ensure peace and justice, but just as frequently cause agitation and a shortage of supply. So, basically the Flowers.

Boros: The PPC and the Boros are both zealous crusaders against villainy and chaos. We stop at nothing to exterminate threats to our society.

Dimir: I kind of explained this one already, but just so it's all collected in one place, I'll say it again. We're shadowy organizations that deny even existing so that we can assassinate people we really dislike while we accrue large amounts of knowledge.

Gruul: The Gruul see themselves as the last remaining warriors who can truly champion the cause of the natural world. Or at least, they used to. Honestly, the Gruul are more of a grim reflection of the PPC than a straight parallel: an example of what happens when we take our duties so far that we forget why we started in the first place.

Golgari: Our work isn't pretty. Our work isn't clean. Our work isn't even moral. But you know what? It has to be done. Everyone else relies on us to make things work normally, so while they may look at us as vile or wicked, they also know that we have to be that way.

Izzet: Question 1, does this thing explode? Question 2, if previous answer was yes, how quickly can I have this thing? Thanks DoSAT/Izzet, you're great.

Orzhov: We are an unparalleled force of glory and greatness. Our leaders are so strong that they have existed since the dawn of our organization. Ignore the savagery, ignore the power plays, and ignore the deception. Because let's be honest, we aren't the most morally grand group in the world, but we think we are, and it's the thought that counts, right?

Rakdos: Kill the Sues! Kill them all! Aha! Haha! Hahahahaha!

Selesnya: You know what the problem with the rest of the world is? They're not us. If they could just understand, if the Suethors could just see what we see, there wouldn't be any problems. And don't listen to the critics. We know our knowledge is pure, the will of the gods and/or authors themselves.

Simic: So, I know everyone says that tenth walker fics and stories by young teens and all that are a bad idea, but we could make it work. Trust us, we're professionals or something, we know what we're doing. And if not, we can just mission our own fics. Surely, making one creation just to get rid of a previous creation is still a good thing.

I think that's all of them. This went on for kind of a long time, but hopefully you get the idea. And if not, TLDR: Ravnica's guilds are super cool and the Magic writers made these groups all relateable on some level.