I think I should start being more game-specific.

I already am pretty rules-specific with the GURPS stuff (and that one In Nomine thing), but that’s because I’m familiar with the rules and requirements for fan-based materials.  What other rules system-specific material would other people like to see? What would be useful? …Currently-supported game worlds a plus, mind you. I’d eventually like to get paid for this stuff, so practicing on systems that take submissions would be a plus.