I've learned a bunch of work-arounds for getting different formats / figure conformers into Poser.

I've EE's 'Crossdresser', but not yet got the knack of making results look non-silly. YMMV. 

FBX items are supposed to import freely. Props are usually much more tolerant than rigged figures, but results range from 'Perfect' to crashing Poser. IMHO, the older the FBX version, the better, so eg v6.1 (~2016) is usually better than recent v7.4. There are honourable exceptions. YMMV.

DS' DUF / DSF props may be exported to OBJ+MTL, either using one of several ($$) utilities, or via free DS' own export tools. I found the latter are much faster when model size rises beyond a few MB, although the UI gives me a prompt migraine. YMMV...

MikoMikoDance (MMD) PMD, PMX and X props may be exported to OBJ+MTL from the free PMX Editor (DA), albeit mirrored L/R by default.
Care: MMD 'TDA' models' T&Cs often prohibit such porting. Please respect such.

SFM items and their VTE textures may be ported to OBJ and eg JPG using free Noesis, but that does not generate an MTL or match them up.

XNA/Lara and related "Gary's Mod" items come as .XPS and several types of .ASCII. Free 'Open3Mod', free 'Noesis' and ($$) 3DOC can convert some of these, often dependent on file version. As yet, Noesis cannot grok XPS as-is, but I've had some success exporting rigged .ASCII (Or .MESH.ASCII) to FBX.

Mariokart64's free utility (DA) will usually convert any XPS, X or .ASCII type to MMD's PMX, rigging included, from where props may be exported as above....

So, I reckon the big gaps are rigged XPS and rigged PMX to Poser-compatible FBX.

Note I've made no mention of tweaking in Blender. Unfortunately, the oft-changing sub-versions of both Blender and its I/O plug-ins mean that export to Poser via FBX has horribly unpredictable results. There seems to be an ever-shifting 'sweet spot', such the same work-flow may export well-behaved models one week, chaos the next...