I'm actually working on two story collections at once now. I had already started doing a short story for a second collection, when it occurred to me that I might like to write a different kind of story. Not just a different plot, but an entirely different approach.
Thing is, I think that different approach might appeal to a different kind of reader. So, I'm going to mush on and write stories using both approaches, and publish them in separate collection when I had assembled enough of them.
The one collection, the one I already started, will be along the same lines as the stories I've done so far, with fairly fleshed-out characters and plots. But the other collection will be full-fledged flights of fancy, fantasies about the ways we wish ever balloon encounter would end up.
These fantasies will mostly be flash fiction, 1000 words or less each, and I probably won't release a collection until there are at least 10.000 words worth. But they are the visions that have been dancing around in my head since puberty, and so I don't think they will take nearly as long to write.
For those who enjoy realistic stories about realistic people, even in works of fiction, this might not be up your alley. But if you feel like taking a walk on the "only in your dreams" side, these might just be the ticket.