Zak S. just swept the Ennies with Red & Pleasant Land, an indie RPG setting that has raised the bar for the whole industry. He also wrote a post that every tabletop gamer who is thinking about how to get some cash for all this work they do on their hobby should read. Go read it if you haven't and then come back here. Don't worry, it's short.
If you didn't do that, the main point of the post is that this is the ideal time to put out whatever weird thing you've been pouring yourself into, instead of trying to worry about what people will pay you for. Just keep the team small and you'll get a big enough chunk of the profits that you'll end up doing better than you would working directly for Hasbro or Paizo, and they wouldn't let you get away with doing what you want to do anyway.
I have a few of those projects going on (though none of them have good names yet). I've posted about a couple; the Kellerlabyrinth and the last stand of the Maya are playable at this point, but not publishable. Kellerlabyrinth is closer, mostly because it's smaller.
There's also a desert city that I've been dicking around with for YEARS now because I knew I wasn't that good a DM when it occurred to me, and it felt like too good an idea to not get right. Petra is a ruined city carved into a desert canyon in Jordan by an ancient people called the Nabateans. The one I'm designing is the city of which Petra was a pale reflection, built by enslaved elementals for a society of sorcerers. They disappeared when they were imprisoned in a time loop centuries ago, and are only just now beginning to escape back into the players' timeline. I've been working on random tables to come up with individual sorcerers and their vaults, which function as microdungeons that are a bit like a community of less detailed seclusiums (that I'm pretty sure actually CAN be built in a half hour or so).
My youngest solo project is the hyperdimensional library of an insane god that I get to fill with all the mindfuckery as I can come up with.
I'm also working on a new project with David McGrogan and Matthew Adams (I think? David says "He is definitely interested") that I don't know if I'm supposed to say anything specific about yet. In Yoon-Suin, I only did the map (easily the least impressive part of a great project) and told David what font to use for the headline text, but this time he's got me doing all of the graphic design (which was probably the second least impressive aspect of that book) and I'm stoked about it.
Time to get to work.