Although site is mostly in Japanese, browser 'auto-translate' works well.
A lot of models are freely available to down-load.
Some need password often found on linked nicovideo page.
Many need sign-in.

Previously, you registered by jumping through complex, multi-lingual hoops, give all sorts of ID. I never managed to join...

Now, you may sign in with twitter or Facebook...

https://bowlroll.net/file/tag/MikuMikuDance
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PMX Editor, free on DA, can export items as un-rigged OBJ+MTL. Handy for props, sets etc.
https://www.deviantart.com/inochi-p...-v1-0-766313588
Care: OBJ is mirrored. If this matters, use editor's 'mirror' tool prior to export...

Truebones' $$ 'PMX to FBX' utility can convert rigged PMD/PMX to Poser-compatible rigged FBX.
Note this first version only ports 'hues', not texture calls...

"Now, you may sign in with twitter or Facebook... "
I wouldn't call this "Easy Login" either   

Well, by *comparison* with previous route that required phone number, a human translator etc etc...


IIRC, a lot of the complex sign-up prompts were images, so neither auto-translated in browser, nor could be copy/pasted to eg Google Translate...

I do not have much of a Facebook 'presence', nor am I among the manic 'twitterati'. But, I can now access most of the nice 'members only' freebies that had eluded me...
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Tangential, though I have a lot of Rendo 'points' towards P_13, I'll not be an 'early uptaker'. I'm staying with P_11.3 until the P_13.1 / .2 dust settles and the price eases...