Wikipedia seems to have a rather broad definition of the term. It thinks Poser, Studio, and Windows 10 3D Paint are 3d modelers.

I'm not sure about DS as I've never tried doing it, and I don't have windows 10 (first I've ever heard of 3D Paint), but I know that in Poser you technically can create models using the various primitives from the library, along with the grouping tool and very precise movements along the x, y and z axis. Dr Geep had several tutorials back in the day showing exactly how to make everything from barstools to houses using nothing but primitives and the grouping tool. Those were my first adventures into creating models back when I first started using Poser. Not sure if those tutorials are still available anywhere tho.

But as for what other people use, if you wanted to make a list you'd pretty much have to list every modeling software out there that's available to the public, as every one of them have been used by someone at some point to create models for Poser. It seems the most common ones used these days are wings3D, Blender, Silo, Hexagon, Shade3D, and maybe 3DS. They're the most often mentioned at least, and most affordable to the hobbyist budget aside from 3DS (which also remains the most pirated 3D software out there, so there's that).