Finished my new MS and I'm letting it sit. I've got a bunch of ideas for what to start next and the future but there isn't really anything to compare them to. My stories don't really seem to line up with anything that's out there.

So is it safe to assume that a story has a big market if you can see a lot of people enjoying it? I can't really say any of them are niche exactly. Mostly action/adventures based on different themes (strife in a witch's world, kitsune troubles spilling over into the human world, a gryphon shapeshifter community and their troubles... fantasy stuff) with a little bit of romance thrown in... but they're not really similar enough in storyline to say This one'll be good for fans of Graceling or That one'll be good for people who like Northern Lights. They're not PNR either, so I can't really pass it off as me switching out the MC's supernatural lover with another mythical creature.

I'm not doing anything experimental with my writing style or story structure and like I said, they're about the characters. So how do I tell if certain stories will have a big market, especially when nothing similar has been done?