Modern and futuristic trains have been previously requested so there will be more of that for sure. There's also a subway train in the works right now that could be used, although I want a couple more styles. Pretty soon I plan to make ruined versions of many of the modern sets as well, so the subway/train sets will likely get ruined versions as well.
Armored/military hasn't been requested so I'll add that.
Organic is interesting, adding that as well.