I want to start using Scrivener to plan a game and am looking for some templates for characters, locations, encounters, etc.
Younger RJBS's answer is still very good, and I largely agree with him!
That said, I have finally produced a template to use to quick-start ideas so that I won't need to putter too much on them, if I stick with them. I will probably continue to tweak the template over time, but only if I keep using it at all.
So, yes, now I have a template for Scrivener for RPG campaigns, and you can use it however you like, too.
I use Scrivener extensively to plan my games. I appear to have about 214 documents for my upcoming game, and I'm pretty sure I'll have a bunch more by the end of the night... but I don't use templates. Every once in a while, I think about whether templates would make things easier, and so far I have never thought so. Instead, here's what I do:
I have the whole project broken into three top-level folders: player's setting book, player's rules documents, DM's notes. Inside the DM's notes I have all my notes on locations, NPCs, plot hooks, specific adventure plans, and so on. Although it seems like I'd have enough locations, NPCs, or whatevers to benefit from templates, I've found that I don't actually repeat much information at all between any two NPCs. Instead, each card just contains a few paragraphs of notes about who the character is, what he wants, and so on. While I could make a template with a few bold placeholders for "Allegiances" and "Motivations," no document is so large that it really would benefit from that kind of organization. Do you think yours are large or complex enough to?
Another question to help decide whether you want a template is: if you don't have a list of sections to write, will you forget to write all the sections you need? For example, imagine that your NPC template includes an "Allies" section. If you don't have it, will you forget to note down allies, and then be hard pressed to figure out who they are, or slowed down trying to find where in the document they are listed? My judgement has been that it's the opposite: those headings would make me make decisions about things like allies and secrets too early, by seeming to pose a question that needs an answer. Instead, I let the question come up during play, and then I can record the answer later.
I still keep track of some things that would otherwise go on a template using tags. For example, I have a "Government" tag that goes on every plot arc, NPC, and location that is closely related to the imperial administration. This is more useful than putting "Allegiance" on templates, because it can be used to build collections, and can show up as a color strip on the document's corkboard card.
So: I also would like to see what people are doing with templates for their campaigns, but so far I have been carefully considering them and continuing to decide that they'd be more administrative overhead than they are worth.
Scrivener 2.0 (the newest version for Mac OSX) has pre-built templates for character and location sketches. But templates can be very easily modified, altering the fields to your liking, and re-used for other purposes. You can even set all of them to have different icons to be discernible at a glance.
I use Scrivener for an epic fantasy novel I'm writing, and I have templates for main and minor characters, for clans, rune castings, magics, religions, etc.