I have to agree with estherau, Semidieu's scrips at Runtimedna are a major boon.

I use his library over that included in Poser, finding it both more versatile and a whole lot faster.

If you use any of RDN'a lighting studio products, you will find his support scripts make them much easier to work with.

Also, if you use the PICK products, he has support scripts that makes working with them much, much easier.

You should also check his scrips for setting up lighting, his scene manager, and Advanced Render Settings - a major boon that also gives you multi pass rendering.

Also at RDNA, you should check out Netherworks scrips. If you use a lot of scripts, then his Palette Master will help you set them up for easy access. He has quite a few handy scripts though, adding things like a camera menu bar, and lights to your memory dots!

If you want to do any morphing in other programs, such as full body morphs or adjusting a figure once it is posed, then the Pose Morph Loader by colorcurvature is available here at Renderosity.