I've been hovering over this subject for long and even trying to make it myself in-game. Most people prefer not to stick to others, as it is more prone to raiders, murderers, burners, stealers ect. And others are simply the people I listed here posing as inoffensive normal people to strike from the inside and betray you. My plan is to form a cooperating, working civilization with people working on different topics or many at a time to gather resources easily. If there was more than one at a time, trading could be even involved with the unique resources each tribe has access to in their dominion. Based in this thought I have decided to classify these civilizations into three different types by size, and about infinite classifications for their type of governing, but I'll name some I think would be common.
Size: 1. Tribe. A tribe controls a very small island or a part of an island. 2. Kingdom. A kingdom controls an entire medium island, or a good chunk of the mainland. 3. Empire. An empire extends to more than a single island, or controls at least half of the mainland.
Government: 1. Democratic Socialism: Resources and food are free for everyone in the civilization. There is no main ruler in charge, decisions are taken with everyone in the civilization. Though socialism/communism might be ideas looked down upon in real life due to the corruptibility of people and it killing millions in general, in game it's actually one of the most, if not the most common government in the civilizations I've seen. People take and give accordingly. Moving on...
2. Monarchist/Theocratic Dictatorship: As odd as they sound they're more common than you probably think. One of the civilization's members or a fictional being is worshipped and served as a god, normally just for the fun of it, but it can escalate to a civilization actually becoming slave to a single member and following his orders. Sometimes, this fails, and a rebellion occurs. The ruler does not work and they decide whether or not people get to eat or take resources.
3. Authoritarian: The entire backbone of a civilization like this is warfare and raids. They do not work, but rather steal and pillage resources from others. Think of it as a civilization run entirely by raiders, that most likely live in the mainland or go on raids with a large navy. They could be nomads, so separating large raider groups from Authoritarian civilizations can be quite hard.
I said I would name a few, as the possibilities are endless for the government of a civilization, but many of these possibilities are simply overlooked and never happen, so I listed common ones.
If you've ever came accross a civilization, please tell me about your experience, the social part of this game is what amuses me and it would help to know more about these civs.