Do high poly models sell if they are not meant for 3d printing?

in general yes, high poly models could sell. Though obviously if the model is also 3d printable or have other qualities that allow for more uses, then there will be more demand for it.

yes sold

Dunno.
And 3d -printing models sells not well.
Only if you have 2000 stolen or generated with buggy "matrix" or "rhinogold" shit-items, glued from library parts.
Or if you are the "studio" that sells models made by asisn "modelers" for promising don't beat them or for two bananas.
Or maybe zbrush-ish hipsterish shit that looks brilliant on the screen and (commonly) more looks like shiny soapy shit after printing, casting and finishing.

In my experience and humble opinion, high poly models can and do sell for many reasons. However, you should provide them with high-quality textures, and plenty of quality renders that are created from the same native file format you are offering the customer.

3d printable models also do sell, but you have to offer them in a variety of formats and you have to have items that are unique in some respect. Offering 3d printable models that just point cloud Photogrammetry Software captures of everyday objects with horrible topological density and very low-resolution textures as STL files will not sell very much. There are millions of those things out there for free already. However, if you can create printable models that can also be used in other aspects of a 3d pipeline but also have the option to be 3d printed, you should do quite well.

Blender native files can sell, but they are only now just starting to become popular commercially. Blender 2.8 is fantastic, and it's really changing the industry in terms of what software is popular. However, the vast majority of Blender users are used to everything being free. They are far less likely to purchase models. In fact, most of the users are themselves modelers, so many of them just create what they need themselves. This could change with Blender 2.8 gaining a vast audience, but this has been the case previously with Blender. The only things that really sell well for Blender are utilities and tools to help make the software easier to use or bring it new features. Those types of things, such as addons or scripts, will sell very well. Models for Blender do not sell nearly as good as 3dsmax or Cinema4d. As I said, that could change quickly though. Blender is gaining traction as one of the most popular software packages out there, so get ready to see a boon in sales for that software very soon.

Fully rigged and textured characters have always been one of the hottest selling products out there, no matter which package they are for. So yes, I'd say there's a good chance it would sell as long as you present it properly and show some good renders of it as well. Offering the FBX is also a big plus because then it's appealing to people who may not want it for Blender but maybe some other package.